Carrie is a very bright, yet religious teen in middle America. Despite her intelligence, she apparently never learned about menstruation, and is terrified when menarche hits in the locker room in front of a bunch of other senior girls. If that timing wasn't bad enough, it gets so much worse when the group of girls just happens to be the vilest group of young ladies ever who then pelt Carrie with tampons & pads, while one of them films the assault and posts it on you tube.
Once you get past this incredulous premise, the rest of the film is actually pretty good. Chloe Mertz is a very modern Carrie, who when assaulted with her mother's fanaticism responds in a very loving, yet borderline-independent way. It's one of the very few ways in which this film differs from the original - the '70s version has Sissy Spacek as a hapless victim of her mother and environment. The modern Carrie is actually relatable - one can understand her rebellious responses to her mother and peers, and see that despite her resiliency, these other influences are relentless in tamping her down.
Where the modern Carrie differs in terms of believability is the picture above... Really, we're expected to believe that the girl above has never been asked out on a date? And that all the pretty girls laugh at her? Really? Really?