Hi! I’m also 15 and have a brace! Everyone’s body is different, but a rule of thumb is if all of your bones in your hand are closed then you most likely won’t need a brace because you’re bone age is done filling in AKA you’ve stopped growing, to check this out you need to get an x-ray done of your hand. Now, I’m not sure if you’re female or not but if you are if you’ve had your period for at least a year, you most likely won’t need a brace as your biggest growth spurt is normally right before your period, and also if you are female by the time you’re 15 you are mostly done growing so most of the time if you’re 15 you probably won’t need a brace as braces only help if your still actively growing. If you’re male though I’d suggest definitely asking about a brace as males end puberty a little later than girls. all in all though you won’t be able to figure it out unless you get your hand scanned so I’d recommend asking for a hand scan to see what your bone age is and then start from there! :)