As long as you told her, or showed that was not what you really meant, then there is no point stressing over it.
I don't get the whole worried about committing thing. What usually happens is you go on dates and hang out with the girl, and eventually you become exclusive. There is no need to worry, because if you are truly unhappy in a relationship, you can leave. It doesn't even get to that point if you are unhappy, because the girl will sense it and leave before you dump them.
Perhaps next time just go with the flow, and see where you end up. But if there is something fundamentally wrong with the girl, (e.g. she's crazy) then consider bailing.
Dont dwell on it, she probably wasn't too interested. Even if she was, the window of opportunity seems to have closed. Move on, if you found one girl you can find another, and most importantly, learn what you can from this.