its difficult baby, I know. I felt chubby at secondary school, with a 25 inch waist (oh what I wouldnt give to get that back) and I look back on it and think I was insane, I was taller and way more developed than anyone else but I could just see the size. As you said though, its the superficial girls that think that. School kids are horrible in there little packs, if its not fat, its your hair, if its not that its your spots, bag, shoes, etc etc
If anorexics werent fretting about their weight their would be some other personailty disorder crying out. I went to dance classes as a teenager and lots of the girls there were anorexic. Even one of the teachers who was 19 was. She used to chew on sugar free gum all day, eat half an apple and drink one can of "one cal". She kind of got over it but now she cant eat food that has been squashed and she eats the same thing, at the same time on each day of the week. She is fastidious about her clothes and hair and has a tonneof other "quirky"traits. This all happened in the 90s when we had the heroin chic look to aspire to. I believe in the 60s and 70s girls were waify too. I dont think its changed, especially as clothing has got bigger now. Growing up is tough.