No person shall be county manager of any such county before he shall have attained
his 25th birthday, but shall not be eligible to hold the office after he reaches the
age of 65 years. He shall be of good character, [and] be of proven executive ability
and experience. No person related by blood or marriage within the third degree, to
any member of the county commission, or who is a member of the county commission,
or holder of a public elective office in the county, or in any city or town political
subdivision located within the territorial limits of the county, at the time of his
appointment or one year prior thereto, shall be eligible for appointment as county
manager.