A picture of the plastron would be very helpful to differentiate the 'type' and possibly the origin of your tortoise. At that age, Cherry-head and some other southern RF's have dark peripheral pigmentation of the plastral scutes at the median and medio-lateral scute sutures. Northerns and Easterns lack that pattern of pigmentation but generally display distinct patterns of their own. The patterns and degree of pigmentation changes with age. See links below: