Shy girl.. should I wait for her?

Hello everyone. Ok, here's the deal. I've had a crush on a girl at college for nearly a year. She's in the year below and has a year left at college and I've just finished education. I'm fairly quiet and introverted and she's pretty shy and spends a fair bit of time by herself but I made an initial approach and we had a few chats here and there over a period of about three months, also exchanging Facebook messages. She described herself as 'extremely shy'. Anyway I eventually asked her out for coffee one day, both in person and online, and she was very enthusiastic about it, saying it sounded like a really nice and good idea and that it would be 'awesome.' Anyway, we went one afternoon and spent about 3 hours together. There were a number of awkward silences, as would be expected between two people who don't talk much anyway, but we managed to have a good conversation, talking about a large range of things including our interests and what we planned on doing in the future. We also confessed to each other again that we were are both quiet individuals and she said that she had social anxiety. We got on well, she laughed at my jokes, and she was all smiles as we said our polite goodbyes. I asked her if she'd like to go again and she said that it was fun and we'd have to go again sometime. However, due to us both being quite busy at consecutive weekends, it has been about a month since we last saw each other. I would have asked for her number but I didn't see the point if we have difficulty talking sometimes so I messaged her again a few times (she doesn't spend a lot of time online and sometimes sees messages a bit late) and she was again reasonably enthusiastic about going again until she sent a message saying that she was really sorry but she didn't think we should meet up again because she doesn't feel very comfortable in social situations. She also said that she is "rubbish at things like this". She wished me all the best with work and exams results and she said "maybe in the future" with regards to a second date. The question is, do I wait for her? If so, how long should I wait or how long should it be before I contact her again?

Put the internet to work for you. via Personal Recipe 2629979