at your age, and for an entire year, i would not recommend it. i have been dating my gf for almost 2 years, and i'm in chile for 6 weeks so we're doing the long distance thing, and its hard as fuck. i love her, and have confided more in her than any human being on earth, and we make it work, but its really hard, even for just 6 weeks. for a full year, especially at your age when you are both discovering new things and people and changing so fast, you will almost definitely grow apart.
break it off, but try to do it on the friendliest terms, maybe even keep it open to the possibility of trying again when she enters college. no sense in tying yourself down now.
that said, if you do really want to try it, skype is your new best friend. also, try do do things in common to have something to talk about (read the same books, follow the same shows, etc). also, you have to trust eachother 110%, jealousy will dissolve the relationship. if either of you don't trust each other it won't work when you visit for vacations, make them COUNT (lots of romantic things together, lots of sex, the whole shebang). i still think you have about a 95% chance of failure if you do try, but i hope this post helps. good luck with whatever you decide to do.