Hi! I'm 17, and I identify on the ace spectrum. I agree that you're never too young to identify as asexual and I also agree that sexuality is fluid and can change. However, I know that, biologically, adolescents don't (or wouldn't) start feeling sexual attraction until they reach a certain age, and for some people that age is later rather than sooner. I'm not saying that a 14 y/o can't identify as ace, but how do you know that you're actually ace, or just haven't reached that age?
I don’t think there’s a way to really know if you’re “not old enough”, but I also think that if a 14 year old feels the need to identify as ace, then that 14 year old should absolutely be free to do so. Whether or not they continue to use the label as they grow up is up to them; the thing to note here is that sexuality is always changing. Regardless if your orientation/label changes because you were a “late bloomer” or because you discovered more about yourself, it doesn’t change the fact that the labels you used in the past were the best fit for you at the time. Choosing labels isn’t about putting yourself into a box, locking it up and never letting it move. It’s about finding yourself, putting words to how you feel, finding others with similar experiences, and so many other things. Not everyone finds the right words right away, and that’s okay!
So if a 14 year old is having different experiences from their peers (assuming their peers are showing interest that goes beyond platonic in other people) and they want to identify as ace- absolutely let them. If they decide the label doesn’t fit in the future, what harm have they caused?
Now I understand some of you are going to say “but they reinforced the stereotype that aces are just immature and will ‘grow out of it’!!!!!” and to that I say: they aren’t the cause of the reinforcement. The people who don’t understand asexuality are.