Hmm, I would continue to hang out with her as you are. As long as you are having a good time together, it'll still make both of you happy. And if still a couple weeks or a month or so down the road you are still having these feelings and having a good time together, then tell her. But don't rush into telling her or tell her if you don't think she feels the same way, it might scare her away altogether from being friends and all.
Never regret something from your past, everything happens for a reason.