My daughters hair didn’t grow for quite some time and dresses interfered with crawling. More often than not people would say, “What a cute little boy!” By the time # 2 came along we did not correct people and just said thank you.
Now days there is quite a bit of androgyny in appearance of people, especially young people. I generally try to avoid saying anything that requires gender identification. If I must, I call what I see. If they are purposefully projecting androgyny they shouldn’t object to people’s assumptions if they are incorrect. If they are projecting a gender, I go with that. If it’s wrong, it’s no crime on my part as I see it.