I own the Biology of the snapping turtle book and its in there yet I'm moving and its not available to me right now. Yet I think its only like 7.5'' these guys are actually built to wait till later in life when they are large enough to sustain larger clutches of eggs and be more successfull breeders over a long period of time unlike other species which can breed sooner and have smaller clutches at first. I'd suspected a female that's 8-9'' would be within recommended size. Yet given the extreme growth which can be seen in snappers I don't think I expect a 2 year old 8 incher to be sexually mature yet I could be totally wrong. I'd say 3-5 years should be a good age.

Xavier