I’m saying 18 or 17 off the fact we got a 5 year time jump with the sequel and he was similar to his pre-Bendis iteration in the first , but we never got a definitive age. That means he was close to the possible ages of 11, 12, and I’m not discounting 13, so youngest he’s 16 and oldest he’s 18.
With comics I have to make a lot of assumptions on ages since they rarely say flat out.