Lowell's Lyndsey Gunnulfsen made her stage debut when she was in fifth grade. At a school talent show, accompanied by her older brother, she tore through a song she learned from the musical comedy "School of Rock."
For Lynn Gunn, as she calls herself now, the movie was practically real life. In seventh grade, she saw Paramore open for Jimmy Eat World, and decided then and there she wanted to lead her own band.
That band, PVRIS, played its first gig in Manchester, N.H., four years ago, when the singer was 17. The group, the first female-led band signed by the independent metal label Rise, released its debut album, "White Noise," in late 2014. The record did a slow burn — and then it blew up.
Preparing a deluxe reissue of the album in April that will include a new single, "You and I," PVRIS has hit the road, opening for Fall Out Boy in arenas and coliseums. The show hits Foxwoods Casino Saturday.
In January, the group made its late-night TV debut, on "Jimmy Kimmel Live!" And in April the dark synth-pop trio — Gunn likes the descriptors "ghostly" and "paranormal" — begins a headlining tour of the UK and Europe. Many shows are sold out already.
"We're kind of being surprised every day, hanging on by the skin of our teeth," says Gunn of her band's mounting success. On the phone during a rare recent off day, she's recovering from a brief illness and packing to hit the road for the next 40 days.
Still, she sounds refreshed, perky even. For one thing, she says the excellent chemistry with her bandmates, bassist Brian MacDonald and guitarist Alex Babinski, has made their rapid ascent a joyful ride.
"We love each other. We love to jam with each other," says Gunn. "We don't know where this will take us, but we'd like to have a career for a while. We still want to be jamming together when we're 50 or 60 and have arthritis, and can't play our instruments the right way."
She credits her older brother, Nathaniel, with introducing her to all the classic-rock staples: AC/DC, of course, but also Led Zeppelin and Metallica (all featured in "School of Rock"). While still in elementary school, she'd pick up his guitar or his drumsticks when he wasn't around.
"He took me under his wing. We definitely fought a lot," she adds with a laugh, "but we love each other, obviously."
Gunn, who identifies as gay and has spoken about her desire to be a role model, comes from an athletic household. Nathaniel is an avid rock climber; his kid sister was a standout catcher on the high school softball team.
"I definitely had more fun doing electives, art classes, and sports" than studying the core curriculum in high school, she says. "I was a super jock, but I was also in the marching band, and I took studio art, graphic design, music theory classes. I was kind of all over the place — I didn't really fit in with any one clique. Looking back, I really enjoyed it, but I stressed myself out academically. I put way too much pressure on myself that I didn't need."
Her parents — mom's a teacher, dad's a builder — were skeptical at first when she abruptly dropped plans to attend MassArt to pursue her performing dreams.
Their dismay "was more about the not going to college," Gunn says. "But when I step back now, they definitely should've been more concerned about my living the quote-unquote rock star life. You're away constantly — it definitely messes with your head. But it's a greater experience, in my opinion, than going to school and being stuck in one place."
Part of her band's allure is Gunn's visual sense: She knows how to create an impression, with her all-black attire and her one clipped eyebrow. In the stylish new video for "You and I," she's turtling, dripping body paint as thick as oil.
Her bandmates — there used to be more of them, back before the band was called PVRIS, when they were more metal — have developed their own sense of style, adding to the overall showmanship, she says.
"When we first started, I was definitely like, 'Maybe wear these shoes instead of running sneakers?' " she recalls, laughing. "But they can dress themselves now. Pretty impressive, actually."
Until recently, the band rehearsed at MacDonald's place in New Hampshire. Befitting their rising standing in the music industry, they've just relocated their equipment and base of operations to Nashville, where there are rehearsal spaces, studios, and music stores in abundance.
"They have all the gear in the world there," Gunn says. They also have Paramore's Hayley Williams, Gunn's middle-school hero, who grew up in nearby Franklin, Tenn.
Now they're peers; Williams even tweeted at Gunn when PVRIS unveiled "You and I" on Feb. 22: "You're an absolute bad ass and your band sounds better than ever. love the new video."
Clearly, Gunn's earned high honors in the school of rock. Now, it's her turn to do some teaching.
Opening for Fall Out Boy. At Foxwoods Casino, Mashantucket, Conn., March 5. Tickets: $45-$65. 800-369-9663, www.foxwoods.com