13 Frightened Girls! (1963)

Candace Hull, the 16-year-old daughter of American diplomat John Hull, in London, is a classmate and friend of many other daughters of diplomats from various countries, and gets invited to lots of social affairs. While visiting Mai-ling, niece of the Red Chinese ambassador she stumbles into a major political secret, involving a murder. Secretly,she passes this information to a CIA agent, Wally Sanders, on whom she has a crush. Candy gets into playing secret agent to the extent of even putting some teen-age seductive moves on the boy friend of her Soviet classmate, but this doesn't work out well because he is a secret agent