(a) An offender commits the crime of sexual abuse of a minor in the first degree if
(1) being 16 years of age or older, the offender engages in sexual penetration with a person who is under 13 years of age or aids, induces, causes, or encourages a person who is under 13 years of age to engage in sexual penetration with another person;
(2) being 18 years of age or older, the offender engages in sexual penetration with a person who is under 18 years of age, and the offender is the victim's natural parent, stepparent, adopted parent, or legal guardian; or
(3) being 18 years of age or older, the offender engages in sexual penetration with a person who is under 16 years of age, and
(A) the victim at the time of the offense is residing in the same household as the offender and the offender has authority over the victim; or
(B) the offender occupies a position of authority in relation to the victim.
(b) Sexual abuse of a minor in the first degree is an unclassified felony and is punishable as provided in AS 12.55.