Hmm... Your question is one I cannot answer, for I have been faced with the same thing.. But I will share with you my observations to apply to your understanding and perceptions.
I am female and I am Seventeen. I have always attempted to be friends with people- I actually cared about them, and things at large in general. I avoided lying at all costs and still, Rejection and betrayal where all I saw. I had not a single friend for ages.
From what I have noted, my maturity and lack of a superficial agenda didn't reach anyone. Those around my age when I too was fifteen (not meaning to sound as if I'm preaching or anything..) thought I was 'weird', as they have grown up only understanding the game that is superficiality; one that so many- especially in schools- played. They learned that to be that way, they could excel in the ranks amongst people around them and be accepted.
Your understanding of the futility of superficiality also probably steers them away from you... You understand that what they do is rather... bleak (for a lack of a better word), so in turn, they don't see you as a player of there game, and therefor do not involve you. Some might even avoid you and think your creepy for that same reason. It is unavoidable..
It may sound cliche, however as time goes on, I am certain you will find someone whom will appreciate you as a friend. There will be a lot of frivolous and shallow people for quite a long while... But you seem pretty awesome, so when you find someone like you in those respects, you will have a very good friend.
Quality and elapsed time... Rather than shallow and sudden.
My suggestion is to perhaps join leagues... Groups. Groups for sports at our age usually is loused with only shallow people... But there is a chance. If you like Art, Some sort of book, video games or some television, perhaps you could find online groups that you could take a look at. You can find groups for all of those things and more on internet blogs... Most bookstores have events, also. But as always, no matter what you do, be safe :)
I actually made really good friends on http://www.Livejournal.com/ , and with the staff at a local Borders books. They are all older, however... So there is always a distance between us. But the people I met on Livejournal actually understood where I was coming from.. But there is always a chance to meet someone around our age that feels the same way. I too hope for that.
I hope I helped at all (and didn't prattle you to death.. With my social awkwardness, I hope I didn't creep you out or anything.) ... And I wish you tons of luck. Take care :)