Firefighters shall not be less than 18 years of age and able bodied. They shall become members of the Volunteer Fire Department only after a six-month probationary period. The City Council, upon recommendation of the Board of Review, may require that each candidate, before he or she may become a probationary firefighter, must possess certain minimum height, weight, education, mental and physical health requirements, and any other qualifications which may be specified by the City Council.