Drivers must be 21 years of age or over. However, if the rented vehicle is a Mighty Highball, Mighty Double Down, Cheapa Hitop, Cheapa Endeavour, Hippie Hitop, Hippie Endeavour, MightyLITE HiLITE, or MightyLITE DeLITE then drivers must be 18 years of age or over with a full and current driver's licence.
There is no maximum age as long as you have a valid driver's licence.