Long-distance relationships are a nightmare. They're only worth it if you're older and are seriously committed to the relationship. If you're a teenager, don't bog yourself down with that crap. It'll only end up hurting you, and you have so little reason to subject yourself to that kind of torment. You're young, have fun. Don't worry about tying yourself up over the girl because you have your whole life ahead of you. You can look forward to complicated bullshit like that when you hit your 20's. Take advantage of your youth and have fun with it.
I manage to "have fun with my youth" and hold a very serious relationship with my girlfriend. If these two forces ever met though, my brain would explode.
Then you're fortunate. My point was that there's no reason to put yourself through misery because of a relationship when you're 17. You've got an entire lifetime ahead of you which will no doubt be riddled with crippling, relationship-based depression and self-inflicted misery! Why go through that when you're a teen? Save that for later, have fun now.