So long as you feel comfortable around her via text/message or whatever, I'd say the next logical step would be meeting in person, where you can see how you guys really interact. I totally get what you're saying about exiting that comfort zone too quickly—my best friend has anxiety that flares when she's not in control of a situation, and that definitely carried over into a fairly recent long-distance relationship she had. She'd never really been in a good relationship before, and he liked to move quickly, which freaked her out a lot, but when she did muster up the courage to tell him to slow down, they worked out a lot better. So if things move too quickly, I think honesty will be your best policy with her. And you. Be honest with yourself, because she's bound to get hurt, too, if you don't listen to your own needs.
Good luck, I'm sure you'll make the right call for you!