Daughter doesn't apply. I'll ask them if 'spawn' is ok. lol (They would laugh.) I guess I just thought there was a set term. 'Oldest' would work. I'll ask them.
Child, Offspring, Kid/Kiddo, Oldest, Youngest, Spawn
https://www.lgbtqnation.com/2023/04/a-guide-to-inclusive-gender-neutral-family-terms/
I don't want to die in Wisconsin. My autistic son (youngest) knows this. I've been waiting to see if he's gonna be ok. Currently he cannot get a different apartment because he's on disability.