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 G.S. 33A-4 or G.S. 33A-5, except that any transferor may have custodial property transferred to the minor at any time after the age of 18 and before the age of 21 by a designation in the following words or their equivalent: "The custodian shall transfer this property to _______ (name of minor) when he reaches the age of ___ (age after 18 and before 21).";
(2) The minor's attainment of age 18 with respect to custodial property transferred under G.S. 33A-6 or G.S. 33A-7; or
(3) The minor's death.