LGBT: Do you think that she will go back out with me after what I did?

I had seen this one girl around school, and I had heard that she was rather promiscuous, and she was bi. She got into one of my cles and I was nice enough to her. When I had known her for about 3 days she asked me out. I agreed, but wasn't really sure since I had heard she had an STD (not true but I didn't know that). I told a few of my friends that I didn't really want to go out with her and she heard so we broke up. Now we are best friends and act like we are still going out. I know her better now and kind of want to go back out with her. If you where her would you go back out with me? I think she still likes me, but I'm not sure. I am planning to ask her back out and explain why I had said I said I didn't want to date her. I don't really want to be rejected though. Should I ask her out? do you think she will say yes again? (this is middle school, so it's not like relationships are really serious).