Section 18-5-15 - Ages of persons to whom schools are open; enrollment of suspended or expelled student(a) The public schools shall be open for the full instructional term to all persons who have attained the entrance age as stated in section five, article two and section eighteen, article five, chapter eighteen of this code: Provided, That any student suspended or expelled from public or private school shall only be permitted to enroll in public school upon the approval of the superintendent of the county where the student seeks enrollment: Provided, however, That in making such decision, the principal of the school in which the student may enroll shall be consulted by the superintendent and the principal may make a recommendation to the superintendent concerning the student's enrollment in his or her new school: Provided further, That if enrollment to public school is denied by the superintendent, the student may petition the board of education where the student seeks enrollment.(b) Persons over the age of twenty-one may enter only those programs or classes authorized by the state board of education and deemed appropriate by the county board of education conducting any such program or class: Provided, That authorization for such programs or classes shall in no way serve to affect or eliminate programs or classes offered by county boards of education at the adult level for which fees are charged to support such programs or classes.