Hollywood Nerd: The beautiful and extremely fit Aubrey Plaza is the shunned valedictorian of her high school. Justified in two ways - the actress is known for playing intelligent outcasts and the character is known to be unpleasant to be around.
Those Two Guys: Brandy's best friends, Fiona and Wendy. Cameron and Duffy are also count.
Twenty Minutes into the Past: The film is set in 1993. While this is partly for nostalgia, being set in the pre-internet era makes it much more plausible for someone to be both as book smart as Brandy to also be so clueless about sex.