Rushing to marry someone to have sex is stupid and naive.
Some would argue that it might be un-Christian. (I personally don't, but it's still really stupid.)
So either, buck up and deal with using your hand until you find the
right woman, or realize that plenty of Christians have sex before marriage and don't get struck by lightening.
As for the girls, don't worry about it.
Focus on building friendships with both genders, and your schoolwork.
When you find someone, you'll find someone.
You can't go committing yourself until both people are really into it for the long run, and since you haven't even gone on a date with her, and she's going away quite a distance, it'd be kind of silly.
Maybe you will find someone at school!
Or maybe you'll find someone AFTER school, somewhere else in the world.
Don't rush things, especially for the wrong reasons.