I came out at 15

I was lucky enough to be in a family that would accept me no matter what.
But depending what country you live in you may find it particularly hard to get treatment at 15, particularly when your parents/ guardians are against it. Even though I was 15 when I came out, I didn't really start pursuing transition until I was 17. That was mainly because until one of my lovely friends challenged the system, it was mandatory to essentially go to court in order to start doing anything and I was not up with that.
...
I don't think coming out in an environment like that at your age is a great idea, unless you have someone that will take you in if your family decides to throw you out. I mean living with dysphoria sucks, but its better than living with dysphoria AND copping sustained abuse, or living with dysphoria and Finding yourself out on the street.
I do think you should start building a support network though, by coming out to people you know will accept you e.g. close friends/ family that will accept and support you when/if you take the plunge and start to transition.
also Kate is right as usual, you should seek out your local LGBT clinic if there is one