Young and Innocent (known as The Girl Was Young in The US) is a 1937 Alfred Hitchcock crime thriller. It's based on a novel by Josephine Tey. It stars Nova Pilbeam, who at 95 is the oldest surviving Hitchcock leading lady. She was in films from 1934 to 1948 but left acting before she turned 30. This is good -Hitchcock with a lighter touch, but still Hitchcock.
BFI Screen Online says, "It is much lighter in tone than most of Hitchcock's previous thrillers, thanks in part to the easy charm of lead Derrick de Marney, and anticipates the successful blend of comedy and suspense in The Lady Vanishes the following year." Rotten Tomatoes has a critics rating of 100%.