“I lost so much hair last year — just stress,” she said. “It’s growing back, in, like, little sprouts. It’s a whole thing.”

Then she laughed. “I could’ve just said ‘thank you.’”

Ballerini grew up in Knoxville, Tenn., the only child in a fairly religious household; she occasionally led the singing at worship service. Her rhythmic sensibility revealed itself early: Her mother has told her, she said, smiling, that even as a baby, she bounced along to music so intently that she would scoot her high chair clear across the room. At home, the stereo was tuned to Top 40 (thanks to her mother), and classic crooners (for her father).

“Any time I smell Bolognese, I hear Tony Bennett,” Ballerini said, “because my dad would be cooking some beautiful Italian meal and blaring that all through the house.”

Her parents split when she was 12 — she used to bad mouth their divorce, she said, but now that she’s gone through one herself, “I have a lot more grace for them” — and she found a refuge in songwriting. “It’s the truest love in my life,” she said.

It helped her get through another trauma, when she witnessed the death of a classmate in a school shooting in 2008. By then, she had started voice lessons and picked up the guitar. After she performed her first original song onstage at a senior recital in high school, she and her mother moved to Nashville when she was 15. “I just had this, like, stupid little knowingness,” she said, that she would find her way in.

She filled her days studying tour documentaries and credits on CMT music videos, searching for names online to learn “who worked where, and what was a Sony, and who was a Hillary Lindsey,” the chart-topping songwriter. By 19, she was signed as a songwriter herself, to the independent label Black River Entertainment, where she remains. Within four years, she was a Grammy nominee.