kind of tricky to tell age that away. some people try to push there animals to reach breeding size quicker. or it could of been a problem feeder they had there for some time. so anything would just be a guess.
i know the 2 local pet shops that are around me keep track of feeding and shedding of the snakes they sell (won't tell you who they got them from) but at least keep track of allot of info they collect as they got the snakes