I'm usually not very good with answering questions in the relationship forum, as I have trouble forming lasting relationships, but when I read your post, I was struck with the thought that everyone deserves to be able to reach out and communicate with others. It sounds like things went very well, so don't be so hard on yourself just because she didn't accept your invitation. That doesn't mean that you aren't worthy. There could be a lot of reasons which had nothing to do with anything you did wrong.

Don't give up. Keep reaching out.