I don't know what to do

Ok, so I hardly know where to begin. I've fallen in and out of love like everybody else, one girl inparticular still holds a part of my heart even though we never dated. She of course has a gf right now so I have no chance. But my real problem is that my friend who had to move all the way to Arizona (I'm in Ohio) is supposed to be coming back here when she turns 18, which is next June. I have no problem waiting, however there is also a chance that she won't come back. We want to date, but a long distance relationship would be too stressful, and she said she would date me when she came back. But I just have this bad feeling that something will happen where she won't be able to, and then I have nobody. I have yet to be in a relationship with anybody, and it feels like she's my only chance to be happy, and if I don't get her, I have nobody. I'm stressin out. :(