Here are my thoughts upon initially reading this:
Quote:
I've allways kept her at bay
after a few months I have her practicly begging me to meet with her
If you let that much time go by, I would expect she would have moved on by now. Put yourself in her shoes. If a girl kept me distant, and then it took me months of begging her to meet up with me... well let's just say for me personally I wouldn't have begged her at all, let alone for months. I would have certainly talked to other girls by then.
Okay, so you met up with her. She's flirting back so that's not a bad thing, but now she put you in her back pocket for some other guy. That could be the feeling she got when you put her at bay. Tables have turned and it bothered you to some degree if you are posting here for advice. Now let's get the ball back in your court.
You're both attending the same party on Friday. Now is your time to shine. Don't follow her around, don't pester her, but be friendly. Say hello and be cool. I would assume there will be other girls there, so talk to them. The guy that this girl initially liked will be the guy others girl like. Get yourself a quick reputation of being funny, confident, etc with other girls. Believe me, she will take notice.