First of, you have to feel comfortable with this whole thing. If at any point you feel weird or unsure about this, pause, or even get out of this whole thing.

If you are uncertain about sharing your email address just yet, create a new one and give that one to her. Do let her know that the new one isn't your primary email address and inform her why.

Finally, let her know that this is all new to you and that you would rather prefer it at a slightly slower rate or have a few requirements of your own. If she is a good domme, she will definitely understand this, and work with you to make you feel comfortable as you ease into this relationship.

Other people will have different suggestions, you have to decide what feels right.

Oh yes, most importantly, ask questions, no matter how insignificant they seem, I got into the whole thing from a dom perspective once online, but I started asking a bunch of questions to a few people here through PMs and by starting new threads. People here are increadibly friendly.