Backstage With Pop's Youngest Rising Star Grace VanderWaal

Two hours before Grace VanderWaal's first big headline show in New York City, her fans are lined up around the block outside the Irving Plaza theater, huddled up against the mid-November chill. The age range is wide: kids in braces and sneakers mingle with older adults, mostly there as chaperones.

Inside, VanderWaal — all of 13 years old, and just one year into her career as a folk-pop superstar — is warming up onstage for her soundcheck.