The custodian shall transfer in an appropriate manner the custodial property to the minor or to the minor's estate upon the earlier of:
(1) the minor's attainment of 21 years of age with respect to custodial property transferred under 72-26-604 or 72-26-605;
(2) the minor's attainment of 18 years of age with respect to custodial property transferred under 72-26-606 or 72-26-607; or
(3) the minor's death.