No not really, it's kind of something, perhaps its stereotypical or something. But it is expected that guys are taller and stronger. It's not always true of course. The other thing, if she doesn't know you're trans, it's kind of a bit more that way. It's also more understandable that you might feel that way. Were her feelings hurt? As a female bodied person, when I was presenting female I didn't care about my size. Nor is something like 5' particularly unusual for a girl, it's not uncommon in males, but more outside the norm. Now I feel a lot different about my size-- though really I know there are a lot of short guys. I wouldn't have thought anything at all about it.
I agree that everyone harbors stereotypical and even supremacist and bigoted thoughts. But I think it's kind of overthinking in this case. But perhaps useful in being aware of them.
--Jay