School: Help

please, please please... I want some help.
I have a 'back to School' party to go to (next month) and i would like some help on costume ideas.
Sadly, i sold all my costume type items when i left chch, and cut off my hair - so no more pigtails of decent length.
so i get to start again, and need to choose: Uniform Student, Teacher, PE Student or Janitor or other - but you will have to suggest what the other will be. and I'm not going as the office lady! The janitor idea appeals to me most at the moment, due to it being a bit different, although i'm not sure how sexy overalls can be on a size 16 woman/girl. of course if i looked like a Tui girl - it wouldn't matter what i wore I'd look hot. but i don't - look like a tui girl that is.

actually i think, after looking at photos from the last back to school party i went to, that it may be better if i don't eat anything either until the party. don't worry, i don't actually have the will power to make that happen! In fact, I did score that night - so fingers crossed for a 'lucky' theme.