Sophia Bunker and Izzy Lev, both 13, are hunkered down in Sophia’s bedroom in St. Paul, a girl cave dedicated to all things One Direction — floor-to-ceiling posters, drawings, books, action figures, a life-size cutout of Harry Styles, press-on fingernail art, even a 1D jigsaw puzzle.

Their allegiances are clear: Izzy wears a T-shirt reading “Future Mrs. Styles,” while Sophia’s preference is revealed by a “Keep Calm and Love Niall” poster. The girls, who will be eighth-graders in the fall, feel lucky to be going to Thursday’s sold-out One Direction concert, while their moms wait at a nearby restaurant. What if — just what if — Niall and Harry rang the doorbell downstairs and said they were here to take you two on a double date?

“I would scream and maybe faint,” Izzy said.

“I would try to play it cool on the outside, but on the inside I’d freak out,” Sophia said.

Linnea Anderson, 13, another hardcore local One Direction fan, is crossing her fingers she’ll be able to scrounge up a concert ticket. “When I started to really like them, it was already sold out,” she said.

Linnea, who will be a ninth-grader this year, noted the dozens of sass accounts — fan-launched Twitter feeds — devoted to 1D, on which girls take turns writing funny captions for photos of the band.

Linnea has tweeted to them “hundreds of times, just like asking them how their day has been, telling them random stuff I did today,” but has yet to receive a reply. She figures she’ll be into 1D for “at least another two or three years. Maybe even longer.”

Carin Anderson, Linnea’s mom, recalls being crazy for David Cassidy as a tween. The devotion of fangirls today is much more intense, she said, “because they have so much more. We only had magazines. You could write letters but you never got anything back. They watch YouTube videos over and over, and interact on Facebook and Twitter, which fans the flames. And then there’s all the merchandise.”

Dianne Lev, Izzy’s mom, loves the friendship-bonding the girls’ passion brings out: “They just enjoy themselves so much, and each other, over it.”