That was one of the age options he gave. _________Children - taking the size and form of the gangTeens - are a bit more developed and between the size of children and adultsAdults - are fully developed and at full dino size______if you mean what size, if you want to do a teen, you can just pick some size somewhere between Petrie and his mother's size. I doubt dinos keep track like, "I'm 13, I"m 16"