#35: Only three of the film’s “teens” were actually teenagers
Although Fast Times at Ridgemont High centers on high-school life, almost the entire cast consisted of actors in their twenties. Only three were genuine teenagers during filming: Phoebe Cates at eighteen, Jennifer Jason Leigh at nineteen, and Nicolas Cage — who had fibbed about his age — at just seventeen.

Everyone else playing Ridgemont students was older, a common practice in Hollywood where long production hours and content restrictions make casting minors more complicated. Despite the age gap, the cast managed to capture the rhythms, anxieties, and humor of teenage life so convincingly that audiences rarely noticed the difference.
