Let me be Frank.
Seriously, call me Frank.
Ok, I'll spell it for you with 2 simple words:
GO TO COLLEGE.
Seriously. Go AWAY to college. It is important at this point of your life to establish some sort of independence, even if it isn't financial independence. And Yes, You will most likely be breaking up with your girlfriend. THIS IS A GOOD THING. Never, ever, for any reason, ever stay in a long distance relationship when away at college. It will absolutely RUIN your time there. I unfortunately know this from personal experience. And please heed my words ---
College WILL be an eye opening experience, particularly if you are so disillusioned with your hometown as you say you are. Your horizons will not only be exponentially expanded, but you will find a new found love/respect/admiration/or general longing for your home and family while you are away. It is normal, expected, and can even be used as an icebreaker at parties and freshmen events.
My recommendation is to GET INVOLVED. With everything and anything. Join a fraternity, write for the school paper, try out for intercollegiate or intramural sports. Work out at the gym. Form study groups. Sing, dance, act, donate, give, and have fun. The more you do, the happier you will be. Many bonds you form in college become lifelong friendships.
As for your girlfriend.. it isn't dickish to break up with her because you are leaving for college. In fact, in the grand scheme of things, it would be dickish if you stayed with her. Just as you deserve to live your own life to it's fullest potential at school, she deserves to do the same with her friends at home. I made the mistake of expecting a long distance college relationship to work, and now I no longer even speak to my high school sweetheart (someone who, at the time, I expected to spend the rest of my life with.) Knowing what I know now, I would have ended it at the outset, as painful as it may be, and we both would have been happier had I done it.
Good luck. College will be the best time of your life. It is cliche to say, but incredibly true.. as long as you stay focused and stay involved.