Sierra Hull, who we celebrate on this Saturday Soundtrack, has been playing music professionally since before she reached her teens. Her debut on the Grand Ole Opry came at age 10, she brought her exceptional mandolin skills to Carnegie Hall at age 12, had her first deal with Rounder Records at age 13, and at age 17 became the first bluegrass musician to receive a Presidential Scholarship at the Berklee College of Music. As a 20-year-old, Hull played the White House. The way I best remember how young she was when she burst on the music scene is from her performance at the Merlefest music festival in 2012. When introducing the band, she noted that the bass player was a good musician, but he was also “the only one of us old enough to rent a van.” I’ve heard Hull play over the years at both the Merlefest and Red Wing festivals, and she’s always had the chops to play amazing bluegrass and traditional music. Her first album post-Berklee hinted at new directions, but it …