First off, you don't know what love is, and chances are, neighter does she. If you both loved each other (not just 'as a friend' bs), it wouldn't be a hard decision for you in the first place.
Secondly, don't worry about loosing her as a friend, you already did. She, specifically, already crossed the line.
Third, yes, give it at least a little time, depending on how serious your last relationship was (although, by your age, I would doubt (hopefully) it wasn't anything too serious). Relationship experts say to wait 6 months after a serious relationship. Although I don't necessarily recommend that long, but you'll know yourself when you can stop waiting because 1. You won't ask question's like "should I wait?"

, and 2. You'll just feel it. The main reason not to start after a break up, in my logic, is after you break up, is the whole rebounding thing. Any relationships started while you are still hurting will be doomed to failure. You need to revert completely back to your orginal self and own state of mind before you can successfully date again.
Lastly, Noz is right... you are just a kid. People change, plans change, etc... There's only a small posibility you'll eventually marry her if you try to hold this serious relationship now. Take it very slow because if you eventually decide you aren't right for each other, you might be able to unwind things and still have your friend.
She is pretty hot though.
Moogle, lol... it's not cool to hit a lady, but a

is a different story. Although, I don't believe I've ever done anything to a

who was deserving. I don't know the story, but I'm betting she deserved at least a

-slap in retailation

.