That has been a big issue for me and my youngest child, formerly my daughter. At 21, my youngest child makes them sound like they are four or five. Though since they are someone who was raised as a girl, presents femme and understands the idea of code switching in certain groups I just use “daughter.” (And I’m so happy mine understands that habits are hard to break and sometimes code switching is important. The drama a friend has undergone because occasionally they referred to their daughter as “he” in a slip “you don’t respect me, you don’t accept me!” is not something I envy.)
I also get the mourning the gender of the child you have. I’ve been lucky in that because mine hasn’t completely rejected the trappings of the gender in which they were raised (they were home over Christmas and now I need to buy more nail polish - some of my favorites went back to college with them. I also lost an eyeliner and a skirt). But going through this I realized that I had a lot of emotional attachment to “my little girl” (I also have emotional attachment to “my little boy” - and since he’s always been very boy, I think it would be even harder with him).
I had an acquaintance I’ve talked to four or five times in my life reach out to me out of the blue over the Summer. Her Freshman in high school has come out as NB and she was mourning the loss of the Senior pictures and the loss of prom dress shopping (as her Freshman has gone for androgyny). That’s tough. Its a minor sort of toughness, unimportant in the greater scheme of your kid being happy - which in part makes it even tougher. People shouldn’t be too tough on parents who love their kids, but have mixed feelings about the whole thing.