IF you're really into her just keep it up. Woo her via email for the next six months. If you can, visit her abroad. That's a grand gesture. If she is really as into you as she seemed to be, she's just defensive right now because your quick dismissal ("Go for it!)really hurt her and now she's punishing you and recovering from the hurt.

She was right to leave because if she would have stayed that's really giving up a lot for someone who waits until it's too late to know what he wants and now maybe you'll appreciate the next opportunity you have with her. Especially since she was probably thinking, "He wants me to stay because I'm leaving but he wasn't so interested when I was readily available. If I stay he'll probably revert back to his initial 'I don't want to get serious too soon' logic and I'll have missed out on a great travel experience."

It's good you didn't (if you didn't) argue with her about how she wanted a relationship and is leaving now that you want one-that would completely turn me off and end any chance of a relationship, it's way to cocky and almost threatening.