Ladies, think about when you and your friends did. If you can hold off till almost then, because kids grow up faster, you’re doing good.
The question is what they should be allowed to wear. My approach is whatever the school allows, and a little more liberal. The school has very strict guidelines, e.g. no nail polish because it wouldn’t be constructive to spend time checking hands. So if the kids wear b’tampt make up, and DON’T break school rules while in school, you’re probably ok. This is assuming this is your school’s approach as well. If their approach is that it’s never acceptable, then don’t go against the school.