The trustees of the University of South Alabama, other than the ex officio members of the board, shall be grouped into three classes as provided in Section 16-55-2. The members constituting the first class shall first be appointed for terms expiring September 30, 1965; the members of the second class shall be first appointed for terms expiring September 30, 1969; and the members of the third class shall be first appointed for terms expiring September 30, 1973. Their successors shall initially be appointed for terms of 12 years each. Commencing on June 1, 2014, successors shall be appointed for terms of six years each.