most young teens aren't mature enough to understand or accept homosexuality anyway.

It's not like gay people start off straight, and then suddenly go awry.
The only reason that kids might not 'accept' homosexuality or understand it is because they believe that it is either wrong or doesn't exist. If a young boy gets a crush on another young boy, obviously he'll try to rationalize that it's not a crush at all if he believe that homosexuality is wrong or that it can't happen.
Don't mind me getting way too serious about this... I've had to stand up for my gay friends and give them support throughout their coming out, so I might take this topic a little too seriously.