like julie, i'd go back as far as my high school days and change the way i was back then. My mum sent me to boarding school, and i hated every second, if i could go back i'd do everything in my power to not have to have gone there. or i'd have gotten myself expelled or something.
if i couldn't make it so that i never went to that posh prison for innocent kids, as julie says, i'd work harder, and stick around to do my A-Levels & go to Uni. And i'd have stuck up for myself a lot more.