Hi Kinkly,
I've been poking around this site for a little while, and joined just now so I could respond to your post, because I'm on the other side of it. I'm not sure how to describe myself exactly yet, because the terminology is so new to me. I was born female, but have felt male or non-gendered most of my life. The gender of my partner has never been a deciding factor for me.
In any case, I'm currently dating an MtoF transperson, and what we are doing is just exploring. Trying this and that. Seeing what feels good to her, and what feels good to me. Some things haven't worked out great, so we're putting those off to the side. Some things have been fantastic and so we keep going with those things. My lover is pre-op, and so while we have had PIV sex a few times with varying amounts of success, I have never seen or touched her penis (well, except with the inside of my vagina). She doesn't want me seeing or touching that part of her. I honor her limit. There are so many other parts of the body to explore, and so many different ways to touch each other.
You said your lady friend is interested in exploring with you, and that sounds great. You are concerned that she will want to engage certain bits of you that you don't want engaged? Then tell her up front that those bits are off limits. You have to be clear and specific. This is no time to be coy with her. You can gauge by her reaction to your limits whether it's a good idea to get together with her or not. Be open to exploring the things you BOTH want to explore together. Be prepared for some things to just not feel great. It's not a failure, it's a learning experience.
Just keep the lines of communication open, and I think you will do fine.