>>1
Are you talking about going to college in different places, or something? If so, you're too young to settle down permanently anyway, and are better off not trying to be exclusive for such a long period of separation.

I was in a long distance relationship with the woman I'm now married to (creepy old man here, sorry) on two separate occasions for a total of about four years. Once when we lived in different countries (2 years), and once when we were in graduate school in different cities (2.5 years). It's not impossible, but it's a ton of work, and takes either a real commitment to do everything that needs doing, or a willingness to settle for the next-best-thing (a non-exclusive relationship, perhaps, or whatever works for you). If you're going to make it work, you have to see each other as often as possible, talk daily, and expect to feel frustrated much of the time. Long-distance relationships have all of the same stressors and disfunctions as close relationships, but many fewer immediate rewards--it's all kind of theoretical. So you have to be willing to deal with it and work your ass off, or you have to be sure you're OK with not dealing and working at it.