Ahh! That's FUCKED UP! What are the freaking chances of that?!
If you don't mind...HOW did she find this forum, that particular post, and on top of all THAT...figure out your nickname?
It's confusing! I would go about it with the saying that seems to keep coming up in my life in the Pick Up Arts: "Honesty is the best policy" I would tell her something along the lines of "Yeah, its true. You caught me, but the only reason I've been doing all of this is because I'm working on myself. I'm trying to develop more positive things in my life, and this community is a big help for me. I just wanted to be able to have the confidence to bring out my true personality around you. I wanted you to see me for who I AM, the real me. And so far I've been able to show that side of myself to you. If you're hurt that I posted something about you that you wouldn't care for other people to read about...then I will take it down. I just want you to know that I never used your name, anything truly personal about you or any real specifics about you and I. I hope this doesn't affect the relationship that we are forming because I feel like it's headed in a great direction and I'd love for us to be able to continue getting to know each other." (sugarcoating or skewing a few facts here or there couldn't hurt

)
Not exactly sure, because I haven't been put in a situation like this....yet... but if I was in your shoes, that would probably be what I'd say. I could be wrong, I could be right...I'm not 100% on it, but this is definitely what I would go with unless I learn differently sometime in the future.
I'm sorry man, that is a shitty, shitty situation that no one here should ever have to experience. HOWEVER, if she can't handle this...and she won't accept any answer you decide to give her then you HAVE to be willing to lose her. That's just awful luck, but sometimes those are just the cards you're dealt. This situation seems very difficult to recover from so be willing to move on to the next batch of women. Hopefully there is no way for her to go about ruining your reputation or interactions with future women. Good Luck with all this, let me know how you handled this and how she took it.
~Muse