And not just any high school. Notre Dame, an all-girls  parochial school in Toledo, Ohio, was the kind of  institution where the nuns would measure a student's skirt length with a ruler. "Every day we'd have to kneel on the floor and have it [no more than] two inches above our knees. I didn't have it supershort, but if you had it too long you were such a dork. You looked like a freshman." Thespian training? Local acting classes and improvs at the nearby Margaret O'Brien's Modeling School, plus school plays. "I was always in the chorus," she says,  covering her face in humiliation. "I was a dancing waiter in 'Hello, Dolly!' and I had to dress like a boy. It was awful. So I never really thought that this would happen." "This" started with the annual International Modeling and Talent Association convention in New York, where, at 16, she landed an agent, then a supporting role in 1997's "The Ice Storm." Enter Williamson, who was casting for  Creek's precocious brood. "She's full of talent, the camera loves her, you're drawn to her," he says of discovering Holmes. "But beyond that, she's just a star in life. The type of person, I believe, who would be a success at anything she did." So far, "anything" has amounted to three more movies ("Disturbing Behavior,"  this March's "Go!" and April's "Killing Mrs. Tingle"), all filmed during Creek's hiatus. The last, which also stars Barry Watson from the WB's 7th Heaven, is a psychological thriller written and directed by Williamson. Holmes describes the movie as very "Kevin," because "everything is so inside-joke and tied in to pop culture." Ironically, the very characters he has created-and the actors who play them — have become part of that culture. "It was very strange and kind of scary," Holmes says about seeing her life story in Rolling Stone last September. The article opened with questions about her fling with Creek costar Joshua Jackson (Pacey Witter) last year. "Suddenly, most of my life was out there," she says, still amiable but slightly perplexed. "Why do people want to know all of this?" "That kind of scrutiny could potentially be very damaging to the average psyche," says Jackson, also 20, during a rare moment on the set not spent hanging with Holmes.  "But Katie carries herself with a grace that really belies  the fact that she's only been working for a year and a  half. She's a wonder to behold." In fact, she handles the relationship question with the air of a people pleaser who  knows she should be more guarded. "Josh and I dated," she says slowly. "We're both single now. And everything's nice. It was pleasant. It was wonderful." She gleefully disparages him on one count, though-and it goes for all her male costars. In her opinion, the cast's weekend jaunts to Wilmington's nightclubs simply aren't as aerobic as they ought to be. "We'll try to get the boys  to dance, and they'll be, like"-she affects a deep  voice-"'We don't dance.' And then they'll say, 'Oh, OK, we'll dance.' But they just get all  embarrassed." Laughing, she's back to lunch-table girl again. More school is on Holmes's horizon; she has deferred twice from Columbia University: "I'm still waiting to see if that's allowed. I think it is." It had better be, since her parents, Martin, a lawyer, and Kathy, a homemaker,  plan to see their straight-A student earn a degree, like her three older sisters and one older brother. In the meantime, Holmes says, "I try to read a lot, because I  don't want to get there and be like, 'Homer who? Kevin Williamson's a good writer, but who's this Thoreau?'" Reminded that the other freshmen won't have conquered the canon either, she wails in mock despair, "Oh, they  will. They'll make fun of me. I'll be this old lady, and they'll ask me to buy them beer." With an animated sob, Holmes cries, "I need some cookie dough!" Someone call Kevin Williamson.