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 § 4504 or § 4505 of this title;
(2) The minor's attainment of 18 years of age with respect to custodial property transferred under § 4506 or § 4507 of this title; or
(3) The minor's death.