I don't think it's necessary to reveal being trans on a first date.
The reason being that there are lots of reasons that people wouldn't want to get romantically involved with people, some of these reasons are assigned sex or a person's gender, some of these are things like mental health issues. There are some people I've met that just don't want to date people with depression for example. Does that mean that I should mention my mental health issues on a first date? No. Does it mean I should mention it before becoming properly romantically involved with someone? Yes.
I have the same opinion for revealing that you're transgendered. A first date does not a relationship make. Dating is all about gradually getting to know an individual and then deciding from that whether you think a relationship is viable. Not everything HAS to be put on the table straight away. People are entitled to their preferences. And yes, this does include preferences with genitals (people can't help what they're turned on/off by), but you don't have to start off on that. There are so many things more important about a person and it can make someone feel really insecure when they feel like the most important, most relevant part of their selves, to other people, is their genitals.