It is tough to say when the dipsos are sexable. I have a hard time with them but things to look for are femoral pores and hemipenal bulges. I would say about 8-10 inches. I try not to say an age because their growth can be really variable from one lizard to another. Good luck. What country are you in and who is the breeder. I don't think anyone in the US breeds them due to their abundance and cheap prices. I know someone in the Netherlands that breeds them and if interested I could give you his contact info because I believe he knows of a few more breeders there. Their breeding is spoadic though-they do not get eggs every year.