A different "ball" game, indeed!
Sorry... Couldn't resist. ;)
I had a hunch that might be the situation. Rarely does a guy have a really good friend-who-is-a-girl that she doesn't know he likes her.
Back in my day (God, I swore I would NEVER use that phrase), it was only just becoming socially acceptable to be gay. I'm a little out of my league, here. I mean, it's my understanding that it's a lot more the norm these days, but I have trouble imagining the school environment has actually improved THAT much.
I guess you're out, based on the first part of your meme. If it's no secret to this guy, and if he truly is a friend, your friendship would probably survive the confession. What will happen depends on him... If he's gay, you'll either start something or get friendzoned. If he's not gay, you'll definitely get friendzoned.
If he doesn't know you're gay, then I'd say coming out to him is the first step. I got nothing for advice on that other than to say there are resources to help you with that. At that point, the last paragraph comes into play.
BUT, in spite of all that, you'd be surprised just how little life in school actually matters afterward. Think about it... High school lasts 4 years; I've been out of school for *GASP!* 22 1/2 years... Worst case scenario, you're miserable for a couple years, and then you're not. And years aren't as long as you think they are.
Good luck!