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 K.S.A. 38-1705 or 38-1706 ;
(2) the minor's attainment of the age of 18 years with respect to custodial property transferred under K.S.A. 38-1707 or 38-1708 ; or
(3) the minor's death.