More than 30 classic songs from the 1950s and ’60s will entertain audiences during “The Marvelous Wonderettes.” The musical, which began a three-week run Thursday at the Cumming Playhouse, transports audiences back to 1958, where they meet the Wonderettes, four girls with big dreams, at their senior prom. During the second act, the girls return for their 10-year high school reunion in 1968.