Honestly, I can relate somewhat. There was a time when I thought I was ace because I couldn't imagine myself having sex with others. Yet, when presented with the idea of being fem in those given situations, I felt waaaay more open to the idea.
Sounds to me like you're going through a similar thought process here, and I think it's worth exploring further. What helped me figure that out was when my trans lesbian friend offered to show me the ropes, so to speak. Really get to understand how sex works for girls. That was a very, very enlightening experience, to put it mildly.
In my case, I found out that I really liked the experience, and it sorta clicked for me that this was the way.