I think often girls dress that way to appeal to boys. If I am right, then this is the situation:
Girl, aged eleven, wears clothes that weigh roughly a tenth of the amount of makeup they have on their face. She does this in order to get herself a boyfriend as soon as possible, because having a boyfriend and kissing and stuff is totally what everyone else does and she can't be accepted by her peers and the society unless she's in some kind of relationship. So, let's pretend she finds herself the ideal boyfriend, just the kind she had been hoping for: five years older, finds the girl's clothes and make-up attractive, kisses her and buys her neat stuff.
Will she be with this guy for long? What if the guy sees her without make-up? What if the police catches them?
I can honestly say this is really a crappy situation. Nowadays, it's so important to appeal to guys and be sexually active and whatnot! When I pass the schoolyard of my old elementary school, the older girls just stand there in their skimpy clothes and try to look cool, instead of, say, playing tag or something, like we used to do at that age. By junior high, they have to have kissed someone, or everyone thinks they're dorks or something. They have to drink like their peers, dress scantily like their peers, be cool and attractive like their peers... No wonder their relationships only last for a few weeks at maximum!
I mean... Honestly! This just makes me so mad to think that they themselves would rob their generation of their childhood. Of course, it can't be their fault entirely, the modern media and their idols are to blame, too. It's just getting seriously twisted.
Sorry if I'm agitated here, this is just an issue that really fires me up. I think it's alarming to see what kid's clothing stores sell today. Also, listen to this little story:
I know a family with two professors as parents. They have two little girls. I don't remember how old the girls are, but both are still in kindergarten. One day, the girls' teacher called the parents, saying, "There's an issue with your girls here at the kindergarten. You see, other girls tease and bully them because they're not wearing fashionable clothes." As if this wasn't alarming and absurd enough, the teacher then continued: "Could you start dressing them up properly?"
It wasn't enough that kids under the age of six bully other kids if they don't have trendy brand clothes. The teacher actually thought the problem was in the clothing instead of the other kids and their parents' morals. I sure hope the world changes a bit before my future kids will reach that age.