DD11 is in the sixth grade. She wears lip gloss, mascara and some eyeshadow, but I won't allow heavy eyeshadow. I told her when she could put on makeup that made her look pretty, but didn't look like she was playing "dress up", she could wear what she wanted. I don't mind makeup on younger girls as long as it's clear they have outgrown the bright red lipstick drawn on crookedly phase. DD11 wears it sometimes, and other times she's in a hurry and doesn't bother.
I think she wore a little last year, too, mostly to social events like birthday parties or a "dance." She probably started a year or so ahead of her older sister, because she's watched DD17 buy makeup for so many years!!!!