I use girl even with adult women depending on who I’m talking to. A lot of women are offended by girl, so I try to only do it when I know it’s ok.
As far as teens, I’d say around 16 I might use young lady. Young woman is kind of odd to me, although I think it is used regularly now. I grew up with “woman” having an undertone of meaning she has had sex. I don’t think that’s how people think of it anymore though.
I’m more likely to call a teen a teenager, when talking about them, especially through age 18. It’s nice that we have a word like teenager in English.
I guess with males it’s different. I wouldn’t call an adult man a boy. Although, I do hear it said. “The boys are getting together tonight.” That sort of thing.
Same as girls, once the boy is a teen, why not just used teenager. Young men can be used also.