I give my number first, too. BUT I've had a few girls end up giving me their numbers after I had already given mine. Why do girls do that? I asked Emily that, and she said she likes the men around her to take the lead, she's old fashioned, and that she really couldn't think of anything creative. I dunno, none of those make sense to me.
That kind of makes my point. If she likes you, then it isn't going to matter. I've had the same thing happen to me on several occasions. I just see too many guys overthinking small things like this that really don't matter in the grand scheme of things. Either she likes you or she doesn't, and there's very little that you're going to be able to do to change her mind if she doesn't.