Revealing mistake: When Dani goes to meet Cort after dark to go swimming, you can plainly see it's daylight out because the sun is shining.
Factual error: While the movie is set in 1957, photos of Elvis attached to a wall were taken in the mid 1960s. The orange shirt shot is from Girl Happy, 1965 and the black and white shot below it is from Roustabout, 1964.