I'm confused on a few points. First, if her mother has always been so career oriented, how was she home schooled and why isn't she anymore? Second, Does Noah actually care what happens to Sarah? The build-up indicates that he might have deeper feelings for her, but when he realizes that she's running away, his attitude is rather cavalier. Third, Is Sarah more than a little crazy? I get that she's isolated, why? The way you describe her appearance (not much) she sounds as if she has the look of a bag lady. Again, why? Fourth, Did she used to be a happy, relatively well adjusted kid (when she was closer to Noah) and some critical incident precipitated a change? Fifth, If so, what? I get that it's a short and that you don't have very long to develop your characters. I like the idea of the Super 8 introduction. Finally, why does the teasing of the other school girls have such a profound effect on Sarah? This could be answered by number three. If, for example, life was great for Sarah and Noah was her best friend until Sarah's dad died a few years ago and Sarah became withdrawn and developed sever depression, that would explain her reactions as well as her dress and loneliness. That can be revealed by having the home-movie introduction show Noah and Sarah as kids playing and being friends (Dad would have to be in some of the clips, like at a family BBQ and him giving her the Wonder Woman sweatshirt) up until her father's funeral (which Noah didn't show up to). The mental illness can be shown by having a prescription bottle for phenelzine (an anti-depressant of last resort) on her night stand when Noah goes to get the money. If Mom had to go back to work because the insurance money from Dad's death ran out, that would explain her having to go to public school.
Just my $0.02, take it for what it's worth.
