Barely 17, Taissa Farmiga earned rave reviews for her work in the independent film, “Higher Ground” before landing the plum role of a troubled teen in FX’s “American Horror Story” from “Glee” team Ryan Murphy and Brad Falchuk.

“Yes, I’ve just done two roles,” says the guileless Farmiga. “Well, there was that first school play that didn’t go well. I had one line, something about pilgrims and corn, and had such stage fright.”

That elementary school play may have marked the end of Farmiga’s acting career had her sister not been actress Vera Farmiga (“Up in the Air”). Vera persuaded Taissa, 21 years her junior, to play her teenage counterpart in her directing debut.

“Acting had always been Vera’s thing, not mine,” admits Farmiga, who is the youngest of seven children and home-schooled. “But when we were at Sundance, I decided I officially loved acting.”

Farmiga says her protective mother wasn’t thrilled with the idea of her taking on the intense “Horror” role, but she convinced her by saying she wanted to play a character that was the opposite of her own sunny self. The work has proved challenging, particularly in a violent scene in the haunted basement.

“I felt real terror, like it was actually happening,” Farmiga says.

To hone her craft, she spends much of her time observing her co-stars Connie Britton and Dylan McDermott.

“I can’t believe that a couple of months ago I was just a normal teen,” Farmiga says. “I would never have expected it, and now it feels so natural.”