(1) Notwithstanding general law, private act, or municipal charter to the contrary, no minimum age qualification for membership on the legislative body of any municipality or city shall be greater than twenty-one (21) years of age at the time of taking office nor less than eighteen (18) years of age as a candidate for election to such office; provided, that a minimum age qualification for such membership, within such age range, may be established by a municipality or city by private act, charter provision, or ordinance if authorized by its charter.
(2) This section shall not apply to any county with a metropolitan form of government.