My universal answer is: no. It is not weird at all. It may be statistically uncommon, but who cares? High intelligence and the ability to throw a 95-mile-per-hour fastball are statistically uncommon, too. There's nothing wrong with this. If we were all identical, the world would not be nearly so interesting.
Writer Ann Lamott once said, "Nobody knows what you really want except you, and no one will be as sorry as you if you don't get it" (she was quoting from a letter one of her teachers had written to her, and the teacher was quoting Lillian Hellman). Lamott was talking about writing, but I think the same thing applies to relationships. No one knows who really makes you happy except you.
If--for whatever reason--you're only attracted to trans men, but date cis men because you think you "should," I can imagine a number of possible advantages. It's easier socially (in most places), the dating pool is larger, and you never have to explain the trans thing to your parents. But are these things worth dating someone who doesn't make your heart quicken?
When it comes down to it, what really matters in a relationship are the micro-interactions you have with that person: the inside jokes, the intimate moments, the quiet moments, the indefinable something that draws you to that person. You can't fake it. And you can't conjure it if it's not really there.
I tried dating femmes for a (short) while, because I thought I "should." After all, my butch friends all liked femmes, and there didn't seem to be many butch or androgynous women interested in dating other butch or androgynous types. But dating femmes just wasn't me. I knew it, but I tried it anyway, and it felt like role-playing. My heart wasn't in it. However common the butch-femme dynamic may be, and however wonderful it is for so many couples, it is not the dynamic that feels most natural and fulfilling to me. Does that make me normatively "weird?" I don't think so. Does it make me uncommon? Maybe. But again: who cares?
As far as I'm concerned, there is not a lot of value to be gained in worrying that you're a femme attracted to only femmes, or a trans guy only attracted to cis men, or a bi woman attracted to everyone except butches. Sometimes terms like "tranny chaser" or "butch fag" are used in disparaging ways to talk about people with uncommon romantic preferences. I think this is because people are threatened by something they can't relate to. And it's easier to call uncommon things "weird" than to try to wrap your brain around the wild diversity of human relationships. In fact, it's SO easy and SO common to label and police and stigmatize and categorize that sometimes even if no one imposes judgment on us, we will impose it on ourselves.
I advise you not to do that. I advise you to pay as much attention as you can to what your gut and heart are saying. The more carefully you listen, the clearer they'll get. And I bet you'll never hear them utter the word "weird."