When I attended the Covedale Center’s production of The Marvelous Wonderettes at a Sunday matinee, there were no young people in attendance. The show’s nostalgic score — girl-themed Pop tunes from the late 1950s and early ’60s (pre-Beatles) — has a nostalgic draw for people who grew up with them. Many in the audience responded to familiar numbers, often knowing them from their first notes. But I’m not so certain many in the audience recognized themselves in the shallow characterizations of Cindy Lou (Kate Mock Elliott), Suzy (Grace Eichler), Betty Jean (Lauren Carr) and Missy (Blair Godshall). That’s not because the quartet can’t sing: They do fine with the show’s vocal requirements in harmonic renditions of tunes like “Mr. Sandman,” “Leader of the Pack” and solo song sets, especially in Act II featuring Carr and Elliott.