Listen to the guys and gals here who tell you she's scandalous. You will move on, and you will find a better girl. It may not be any time soon, but it will surely happen. She's worth not a minute more of your time.
Back when I was 16 (OMFG I sound retarded) a similar situation happened. There was this blond haired blue eyed goddess I casually knew for a few years, but never got the balls to ask out. My junior year an old friend of mine I knew from back in kindergarden transfered over. We hung out a good bit and he got to know her too. Except he had the balls to ask her out. I wasn't jealous in the least bit because it gave me a chance to know her better by hanging with her more. And I had my shot, so I couldn't whine about it.
This girl loved to party, there really were no limits. Eventually she dumped him. One day she just showed up at my house and said she wanted to go out. Man that was a really fun time, she was too f'ing fun and too f'ing good to be true....
Sure she did things I didn't like (hopping in the pool at a party in a bra and thong in front of other guys), but she was with me, and the crazy wild monkey s3x more than made up for anything.
We eventually broke up, and my old friend and I got into a knock down drag out fight over her (lost him as a friend because of the stupid fight. Never, and I mean never get in a fight over a girl).
Years later I ran into her. She looked wasted away. Found out she got into crank, coke, extasy, whatever. Just think of her as the suicidal "Jenny" (but I swear I'm not forrest gump🙂)! She never learned to let go of the parties I guess.
The moral of the story..........enjoy it while it's fun.