Foster kid is a different situation but in general seriously don’t bring someone else’s kid to their first haircut. Thats an important moment for parents. It’s a major milestone, especially with girls. That original in-utero hair behaves different.
Three years isn’t that weird. I know a girl who was 4 for her first. She had the most gorgeous, long curls. It was really hard for her mom to get rid of those.
Know a couple boys who were each three too. They look like totally different kids once they lost all their baby curls.