Mary Elizabeth is a character in Perks Of Being Wallflower, as well as Charlie's first EVER girlfriend. In the film, she is portrayed by Mae Whitman.
Mary Elizabeth, though funny, doesn't care what people say and think of her. She is very self-determined.
Charlie goes on his first date with Mary Elizabeth, a friend of Sam and Patrick’s. She is intelligent, rebellious, and opinionated, and it is with her that Charlie explores his sexuality for the first time. Mary Elizabeth takes pride in being interested in the trappings of counter-culture (like punk rock music and edgy hairstyles), but also enjoys the comforts provided by her wealthy parents. Although Mary Elizabeth thinks of herself as Charlie’s girlfriend, he doesn’t find himself very attracted to her or even like her all the much, but their relationship drags on because he is afraid to tell her that he doesn’t want to date her.
Mary Elizabeth breaks up with Charlie after a game of truth or dare where Charlie was asked to kiss the prettiest girl in the room. Instead of kissing Mary Elizabeth like everyone expected him to, he kissed Sam which caused Mary Elizabeth great sadness. The only reason Charlie dated her was to make Sam jealous but Sam didn't seem to care.
She briefly dated Charlie, but Charlie becomes frustrated with their relationship because he believes she doesn't seem to care about what his opinions are and she just keeps talking and talking. Their relationship and the whole friendgroup was shattered when the truth or dare incident happened but was repaired after a conflict that included charlie, patrick and brad with his friends in the cafeteria.