Don't go on a more restrictive diet! I'm vegan and I don't think eating less protein is the answer.(maybe eating less or no animal protein is good) It sounds like you need MORE calories, not less. Eat healthy: whole grains, veggies, beans, etc. I've seen way too many trans women who starve themselves thinking that it will help them pass.
Let the hormones do their thing, it takes time AND it's cumulative. Kinda like the snowball rolling downhill, starts small at first, but keeps getting bigger.
I agree that there are lots of athletic women out there, so no worries about being a lean, muscular woman!