You are going to need to reach a calm and joyful place with your desires, no matter how this friendship goes (and she certainly sounds like a thoughtful and kind hearted friend).
Perhaps desensitize yourself to the guilt and shame you feel by wearing some small (hidden) feminine item each day; sleep in something pretty, etc.
Spend some time watching some of the films and documentaries that we discuss in this forum...ask yourself how they make you feel as your watch them.

Purchase and read some of the many books that CD/TG authors (and loved ones) have published. See where their experiences intersect your own.

Set aside time each day for quiet comtemplation of the days events, your feelings, frictions that you felt, etc. You'll discover how much noise and racket really surround our
modern lives once you turn off the television,radio, and internet, even if only for 30 minutes.

Once you've found that quiet center inside of yourself you'll be ready to enjoy who you are more fully...and maybe there will be parts of you that you hadn't even recognized before.

Good luck!