The sad reality is that because of most public school environments, you're very lucky to even have open homosexuals and lesbians; my school did not get it's first lesbian until I was in 11th grade, and from then on, only a few more girls came out as lesbian. A few guys were also flaming homosexuals, but constantly denied their orientation (until graduation day.) Absolutely no transgenders and not really any gender benders were in my school, although gender bending trends were extremely popular (all the guys shaved their legs, wore skinny jeans, had long flowy hair, weren't into sports, cars, or labor jobs, ect ect).
Basically, with teenagers, the reality is that most teenagers are not well-developed people and for the most part, there are more older trans because it's something that tends to develop after all the sexual and social pressure of being a human being fades away; teenage years are either filled with the people who are normal or aren't normal and desperately try to be. However, if there are any teenage trans in your town, I truly suspect they'll be at meetings or otherwise extremely open-minded sources; a large college is probably the best place to look.
The sad thing is that being transsexual is not yet cool enough to be a part of a teenage society in any form, really. As it is, gender benders are popular, homosexuals are fairly liked (especially if they deal drugs and aren't annoying, or belong to some sort of art-->-bleeped-<- culture), any sort of androgyny is seen as something godly, and generally there's less straight, stereotypical people than not. However, a true transsexual, especially the medical transitioner and firm cross-dresser, is the type that young people as a whole just still do find scary and strange - society is just now catching up to gays.
Thankfully, I think icons such as Jeffree Star and Chris Crocker have pushed acceptance a long way with young teens; some trannsexuals in youth ages can fit in well and meet many friends by adding an alternative, music-based, or comedic side to their look and personality. Anyway, all this is just talking about acceptance in general, because as long as you have friends who love you, it makes the need to talk to another transsexual much less strong, but if you want to meet a true blue, I'd bet the best place to look is still a large college campus; I'm sure they'd try to let a non-student attend a Trans, Gay, or whatever Meeting....
