Should I go ahead and move on?

I realize this is a rather stupid question, but I seriously need help. Last night, I was talking to a girl on Facebook. We met not too long ago, maybe a few weeks or so ago. She just recently broke up with her boyfriend...who just so happened to be my stepbrother. I think I could've done the single most STUPIDEST thing ever. Even after finding out she's still into my stepbrother, I kinda told her I liked her. I got turned down, and even after that, I still can't get her out of my head. Should I wait until she's over him to try again, or just move on completely? I'm sorry I took up so much of your time, I just needed help. Thanks :)