If your T is happy with e-mailing, go for it! I first disclosed stuff about my T that I just could not say in a 3-page letter, and brought it to him to read. He didn't read that one in front of me, but he has read other things in front of me. In any case, sometimes writing just helps a lot.

Good for you for getting it out there. It will suck at first, but you WILL feel better. Just think about how ok she was with your romantic feelings, and also what she said about looking forward to getting a message from you. This stuff is really important, and the more information you can give her, the richer the work will be.

You can do it!