As a teen in the late 80's/early 90's my friendship group and I were not any different. It just wasn't on social media.
I was away at school and the majority of girls would only wear or use certain brands. I don't remember this at 11 or 12, but certainly from the fifth form (year 9) onwards.
Rolled up school skirt - yes
Hair only worn in a certain style - yes- mostly a ponytail with no fringe and one or two side bits hanging down.
clear mascara and lip gloss on a school day.
would only wear loafer style shoes at school.
clear mascara and rose lip balm with clear gloss on a school day
Sun in, shaders and toners were frequently used in my dorm at weekends.
Swatch pop watches, Naf Naf, Levi's and Benetton/ Sweater shop were the mufti / home clothes favoured brands .
If you didn't have the above brands you were looked down on ( V wrong), but teens from the year dot have always wanted to fit in mostly.
It isn't any different for teen girls today - I see it all the time when dropping teen DD off at her school. The only difference is that the marketing is instant and has gone global !