Please take this the right way: obsession isn't healthy and is a long road to ruin. It's understandable that you'd be sad she is moving away, but saying the only happy part of your day is when you talk to her, or see her is not good.
It would put too much pressure on your relationship (if one were to develop); if she didn't love you with the same intensity she might feel guilty and pull away, or you might try too hard to become perfect for her out of fear of losing her and end up losing yourself.
That being said: enjoy your time together now, and stay friends when she moves. You're way young and will certainly love again, and again, and again.