DAVIS, Judge:
T1 Matthew Wallace Peterson appeals his convictions of two counts of aggravated sexual abuse of a child, first degree felonies, see Utah Code Ann. § 76-5-404.1(4)-(5) (Lexis-Nexis 2012); one count of rape of a child, a first degree felony, see id. § 76-5-402.1 (Supp.2014); one count of object rape of a child, a first degree felony, see id. § 76-5-402.8; and one count of tampering with a witness, a third degree felony, see id. § T6-8-508(1) (2012). We affirm.
{2 Peterson argues that the evidence presented at trial was insufficient to support his conviction on any of the five charges. When reviewing a conviction for sufficiency of the evidence, we review the evidence and all inferences which may reasonably be drawn from it in the light most favorable to the verdict of the jury and will reverse the jurys conviction only if the evidence, so viewed, is sufficiently inconclusive or inherently improbable that reasonable minds must have entertained a reasonable doubt that the defendant committed the crime of which he was convicted. State v. Hales, 2007 UT 14, ¶ 36, 152 P.3d 321 (citations and internal quotation marks omitted).
I. Aggravated Sexual Abuse Charges
13 Peterson first asserts that the State failed to present sufficient evidence for the jury to find either that he held a position of special trust with respect to the child victim (Child) or that he penetrated her vagina when he touched her with his finger. In order to convict Peterson of aggravated sexual abuse of a child, the jury needed to find at least one of these aggravating factors beyond a reasonable doubt. See Utah Code Ann. §$ 76-5-404.1(4). We agree with the State that the evidence was sufficient for the jury to have found both factors.
A. Penetration
$4 The penetration factor required the jury to find that Peterson caused the penetration, however slight, of the genital ... opening of the child by any part or parts of the human body other than the genitals or mouth. Id. § 76-5-404.1(4)(J). At trial, Child testified that on two separate occasions, Peterson touched her private with his finger underneath her underwear. She explained that by private, she meant her front private used for [gloing to the bathroom and distinguished it from her bottom. She also specifically testified that when Peterson touched her private with his finger, it went in her private. Peterson argues that Childs general reference to her private, as opposed to her vagina, was insufficient to establish penetration. He also points to the testimony of the witness who performed a physical examination on Child that children generally do not know how to express the difference between touching and penetration of their genitals. He asserts that this makes Childs testimony that Peterson put his finger in her private insufficient to establish the penetration aggravator. We disagree.
15 If believed, Childs testimony establishes, at a minimum, that Peterson put his finger between the outer folds of Childs labia, which is sufficient to constitute penetration. See State v. Simmons, 759 P.2d 1152, 1154 (Utah 1988). In sexual abuse cases, child witnesses frequently refer to genitalia as privates; a childs failure to use an anatomical reference does not make her testimony insufficient, so long as the childs meaning is clear. Cf, eg., State v. Taylor, 2005 UT 40, ¶ 3, 116 P.3d 360 (indicating that the child witness had testified that the defendant told her to suck on his private and described it as tasting like urine); State v. Pritchett, 2003 UT 24, ¶ 16, 69 P.3d 1278 (indicating that the child witness had testified that the defendant put his index and middle fingers into her private area and that he sticked [sic] his privates inside her private (internal quotation marks omitted)). Here, Childs clarification that she was referring to her front private, which she uses for [gloing to the bathroom sufficiently indicated that she was referring to her vaginal opening. And unlike in other cases where evidence of penetration has been held to be insufficient, Child specifically testified that Petersons finger went in her private. Cf Simmons, 759 P.2d at 1154 (holding that the evidence of penetration was insufficient where the victim testified that [the] defendant put the tip of his penis on her labia); State v. Pullman, 2013 UT App 168, ¶ 13, 306 P.3d 827 (holding that the evidence of penetration was insufficient where the victim testified that the defendant tried to put his penis in her butt but that she pushed him away before it went inside). Whether Child had a complete understanding of what it meant for something to be in her private was a credibility question for the jury. But her testimony that Peterson put his finger in her private, if believed, was sufficient for- the jury to find penetration.
B. Position of Special Trust
146 The evidence was also sufficient for the jury to find that Peterson held a position of special trust with respect to Child. A position of special trust is one that puts the defendant in a position of authority and gives the defendant the ability to exercise undue influence over a child. State v. Watkins, 2013 UT 28, ¶ 39, 309 P.3d 209 (quoting Utah Code Ann. § 76-5-404.1(4)(b)). Examples of positions of authority are enumerated in the aggravated sexual abuse of a child statute and include babysitters and adult cohabitants of the childs parent. See Utah Code Ann. § 76-5-404.1(4) (LexisNexis 2012). Child testified that Peterson lived with her family and sometimes looked after her when her mother was at work or visiting Childs great-grandmother in the hospital. She testified that Peterson was responsible for feeding and taking care of her when her mother was away and that she was required to pay attention ... and listen to what he said. Childs mother testified that Peterson lived with her and that he regularly picked Child up from school, fed her, and helped her with her homework. © Childs mother also testified that Peterson frequently tended Child while the mother worked, visited the great-grandmother, and attended social events. Peterson told the investigating detective that he was always taking care of Child. This evidence supports a finding that Peterson was both a babysitter and an adult cohabitant of Childs mother and therefore held a position of authority. It also supports a finding that he was able to exert undue influence over Child because she was frequently left alone with him and he was given charge over her such that she believed she was expected to listen to what he said. Accordingly, the evidence was sufficient to support a determi-" nation that Peterson occupied a position of special trust with respect to Child.
II. Rape of a Child and Object Rape of a Child Charges
17 Peterson next asserts that the State failed to present sufficient evidence to support the rape of a child and object rape of a child charges. First, he challenges the rape of a child charge on the basis that Childs testimony was insufficient to support an inference that he touched Childs vagina with his penis. Although Childs head was covered with a pillow at the time of the events relating to the rape charge so that she did not actually see Petersons penis, Childs testimony was sufficient for the jury to have drawn a reasonable inference that he used his penis to penetrate her vagina. Child testified that she heard a zipper being unzipped and she felt something that felt like skin touch her private. She testified that it went in her private and that it was uncomfortable for her. She testified that although she did not see it, she believed it was Petersons private because she heard the zipper and [iJt didnt feel like his finger and it didnt feel like the device that he had previously used on her, see infra 1 8. Reviewing all inferences which may reasonably be drawn from [the evidence] in the light most favorable to the verdict of the jury, we cannot conclude that this evidence was so inconclusive or inherently improbable that the jury could not have convicted Peterson of rape of a child. See State v. Hales, 2007 UT 14, ¶ 36, 152 P.3d 321 (citations and internal quotation marks omitted).
T8 Peterson also argues that the evi-denee was insufficient to support a conviction for object rape of a child because DNA evi-denee found on the vibrating device does not lend itself to the inference that Peterson used the device as [Child] described. On the contrary, the fact that DNA matching Child was found on the tip of the vibrator corroborated her testimony that Peterson put the small end of the vibrator into her private. Analysis excluded Peterson-but not Child or her mother-as the source of DNA on the vibrator control. This result could be viewed either as exculpatory or as consistent with Childs testimony that Peterson washed off the vibrator after he used it on her. In any event, it was the jurys prerogative to weigh Childs testimony in light of the DNA evidence, and Childs testimony, if believed, was sufficient to support a conviction for object rape of a child. See State v. Fedorowicz, 2002 UT 67, ¶ 40, 52 P.3d 1194 (When we examine a challenge to the sufficiency of the evidence supporting a jury verdict, ... [we} assume that the jury believed the evidence that supports the verdict. (citation omitted)); State v. Workman, 852 P.2d 981, 984 (Utah 1993) (When the «evidence presented is conflicting or disputed, the jury serves as the exclusive judge of both the credibility of witnesses and the weight to be given particular evidence.).
III. Tampering with a Witness Charge
T9 Finally, Peterson argues that the jury could not convict him of tampering with a witness in the absence of evidence that he believ[ed] that an official proceeding or investigation [was] pending or about to be instituted at the time he allegedly threatened Child. See Utah Code Ann. § 76-8-508(1) (LexisNexis 2012).
110 Peterson relies on State v. Bradley, 752 P.2d 874 (Utah 1985) (per curiam), for the proposition that the State had to prove that Peterson believed an official investigation was pending or underway at the time he threatened Child. See id. at 876-77. However, Bradley relied on an earlier version of the statute, see id. at 875-77, which permitted a person to be found guilty of tampering with a witness only if the person acted [ble-leving that an official proceeding or investigation is pending or about to be instituted, Utah Code Ann. § 76-8-508(1) (1978). In 2004, the legislature added or with the intent to prevent an official proceeding or investigation to the statute. Act of May 8, 2004, ch. 140, § 8, 2004 Utah Laws 592, 594-95. Thus, under the current version of the statute, it was unnecessary for the State to prove that Peterson believed an official investigation was pending or about to be instituted if it could prove that Peterson acted with the intent to prevent an investigation in the future.
{11 Peterson also relies on our more recent decision in State v. Jones, 2014 UT App 142, 330 P.3d 97, cert. granted, 341 P.3d 253 (Utah Nov. 25, 2014). While the Jones court cited Bradley in support of its conclusion that the State had failed to present sufficient evidence of witness tampering, it ultimately determined not only that there was no evidence that the defendant believed that an official investigation ... was underway, but that there was no evidence that he believed such an investigation would be imitiated in the future. Id. 131 (emphasis added). Thus, in Jones, the State failed to present evidence that the defendant acted with the intent to prevent an official proceeding or investigation. Utah Code Ann. § 76-8-508(1) (LexisNexis 2012).
12 Conversely, in this case, Childs testimony was sufficient to support a determination that Peterson acted with the intent to prevent an official proceeding or investigation. Child testified that on one occasion, Peterson chased her into her room and pulled her hair. She told him that she was going to tell her mother that he had touched her inappropriately. He replied, [If you tell your mom Im going to kill her. Given that Petersons threat was in direct response to Childs threat to disclose his illegal actions, the evidence was sufficient for the jury to infer that Peterson threatened Child with the intent to prevent an official proceeding or investigation and was therefore sufficient to support Petersons conviction for witness tampering.
IV. Conclusion
{13 For these reasons, we conclude that the evidence was sufficient to support Petersons convictions on all five charges. Accordingly, we affirm.
. The parties dispute whether Peterson adequately preserved his arguments for appeal. However, as it does not alter the outcome of our decision, we assume for purposes of this opinion that they were preserved. See generally Patterson v. Patterson, 2011 UT 68, ¶ 13, 266 P.3d 828 (Our preservation requirement is self-imposed and is therefore one of prudence rather than jurisdiction. Consequently, we exercise wide discretion when deciding whether to entertain or reject matters that are first raised on appeal.).
. In State v. Watkins, 2013 UT 28, 309 P.3d 209, the Utah Supreme Court interpreted the enumerated list of individuals in the statute as identifying individuals who hold positions of authority, not necessarily positions of special trust. Id. 1122-38. Thus, even if the State proves that a defendant occupied a specifically enumerated position, it must still prove that the defendant is able to exercise undue influence over the victim by reason of that position. Id. 120 (citation and internal quotation marks omitted). The legislature recently modified the definition of position of special trust by separating those holding a position of authority that enables them to exercise undue influence over the child from other enumerated individuals, who are expressly defined as occupying a position of special trust. See Utah Code Ann. § 76-5-404.1(1)(c) (Lexis-Nexis Supp.2014). However, because Peterson was convicted under the previous version of the statute, Watkins is controlling here.