There is no way to tell age by weight or size. I have an 06 female Mojave that is 650 grams and just under 24" on the other side I have an 08 Female poss het snow that is the same size. I have an 04 male pastel thats 1500 grams then I have a 04 male Het Pied thats 850.

There is no way to tell their age which is why record keeping is so important.