I think you can buy her a mild cleanser & a lotion as the first step to keep the skin coniditon proper. Perhaps a cleansing mask is also worth using once a week.
I think brand like Avene, H2O, Aveda, Kiehl's, Netrogena are all ok as skincare for 10-something teens. Though a bit costly, it worth. Skincare is very important to girl.
Not recommended to use those "cheap"brands like 花王 - they are too "harsh" for girl's skin - only wash away the oil & the skin will turn dry when she get older.