If a pupil 21 years of age or older, or a pupil 19 years of age or older, has not been continuously enrolled in kindergarten or any of grades 1 to 12, inclusive, since his or her 18th birthday, any attendance credit for coursework he or she is pursuing through independent study shall be eligible for apportionment only if it is one or more of the types of courses set forth in paragraph (1) of subdivision (a) of Section 51225.3 or any course required by the governing board as a prerequisite to receiving a diploma of high school graduation.
This section shall become operative on July 1, 1990.