Students shall be allowed to continue their enrollment at the grade level in a school division commensurate with their grade level, including kindergarten, in the local education agency in the sending state or foreign education agency in the sending country at the time of transition, regardless of minimum age. A student who has satisfactorily completed the prerequisite grade level in the local education agency in the sending state or the foreign education agency in the sending country shall be eligible for enrollment in the next highest grade level in a school division, regardless of minimum age. A student transferring after the start of the school year into a school division shall enter the school on his validated grade level from the local education agency in the sending state or the foreign education agency in the sending country.