Asking the breeder (not necessarily the seller or pet shop), assuming they're candid about it (and not selling them too young).
If that's not possible/practical, I'd post a pic (new thread in
General entitled something like, "
How old do I look?" with the chameleon sitting on a ruler or dowel marked off in inches, with tail extended as best possible.
If there's another/better way, I'm all for learning something new today.
If she was (the recommended) 3 months when adopted, she would have been born in June, which would make her ~9 months.
At any rate, she's probably gravid now and looking for a place...