She was and is a jerk, you are okay, just chalk it up to experience, don't let it turn you into a jerk too, and don't let one experience with someone like that color your judgment.

her mom & dad need a good ***** slap and you need to let it be a lesson to ya... It could have been much,much worse bro...

Alright first of all, look at the positive. Dude you had a date, I'd kill for one of those.

Second you got rid of a loser quickly and without a lot of hassle.

$20 is a cheap learning experience, most cost thousands.

Four, she had to be somewhat attracted or you wouldn't have made the cut to be dumped on, which means your attractive to women, and if I read your post correctly bi-sexual women. You're young, take advantage of that while you can.

Five, let your brother mess with this girls head, she deserves it.

Six (this might be a stretch) you're newly single, nothing is quite as attractive to women as a good man on the rebound.

See a lot of positive stuff here, work with it.