The worst thing that can happen is that she will say no. Not every girl is going be interested in you. It's fine. You ask another girl out and she will say yes.
Keep overthinking asking her out, then I get anxious about it, eventually not approaching her at all. Any Advice?
You are right here in that you're over thinking this to the point where you're actually talking yourself out of this. There is nothing to this but to actually do it and whats the worse that can happen? She says no but then again she may accept your offer so talk to her and see if she will talk to you and if not, forget asking but do something before someone else does before you and then think what youre going to feel like. Good luck
Just ask her and have a few ideas in mind as to where you could go. If she turns you down just say, ok, enjoy the rest of your day (smile) and let it go.