Diana, that is similar to my experience. I also wrestled with the (obviously false) notion that there weren't any trans lesbians. That bit of heteronormativity made it tough for me to make sense of things. I think it's one of the reasons a lot of gay trans people take longer to transition.
Valerie, I didn't think you were being offensive. Sometimes people just don't understand other people's experiences. As long as you're open to hearing about them, that's fine. Also, sexual hang-ups aren't a really big deal. Sometimes there's something deeper behind them (racism, transphobia, etc.), but if you don't want to have sex with someone, that's justified. I can admit that I share some of your feelings -- I wouldn't want to date another trans woman, regardless of sex, because she would just remind me too much of my own insecurities. And yes, that's kind of transphobic. I'm working on it. But the important thing is that whatever your hangups, you treat people with the respect they deserve.