Each member shall be subject to compulsory retirement according to the rules of the government in which he is employed, except that any member able to perform his assigned duties shall not be precluded from serving:
(1) At least twenty (20) years if the member's participation date in the fund is prior to March 14, 2013; or (2) At least twenty-five (25) years if the member's participation date in the fund is on or after March 14, 2013.