Should you wait to sing the blues until your voice has changed? That unlikely question is central to this debut by Michaela Rae Knox, who cut Backbone when she was just thirteen. Her guitar playing is plenty solid, if not exactly innovative — unless you've never heard Stevie Ray Vaughan. But the novelty value of her instrumental precocity crumbles when she opens her mouth. Covering Buddy Guy's "Mary Had a Little Lamb" must have seemed like a cute idea, but it's way too cute, like a gag from a Disney Channel sitcom. (Instead of Hannah Montana, how about Hannah Mississippi?) Instrumentals like "Sin Nombre" and, naturally, "SRV Shuffle" are far more diverting than "Trust in You," in which she warbles, "Didn't come to sing/Just came to play." Good plan.