At the fitting for her first runway job—for avant-garde designer Alexander McQueen in 2003—Gerren Taylor couldn't wipe the smile off her face. But she had to. "You're going to show your baby teeth!" warned her agent. Keep your mouth closed and "they won't know if you're 12 or 16 or 21," L.A. Models runway division director Crista Klayman recalls telling her. Just weeks earlier the 5'10"-tall 12-year-old was spotted on an L.A. sidewalk by one of Klayman's colleagues, who suggested she could model. "I begged my mom to let me," says Gerren. A makeup artist shaved Gerren's legs for the first time, avoiding scabs from playground scrapes, and soon she was strutting alongside veteran models—and fitting right in. "I just shook my hips and gave attitude," says Gerren, who loved to watch the Victoria's Secret show on TV and decorated her room with pictures of Tyra Banks (whom, coincidentally, Klayman had discovered). At New York's September '03 Fashion Week she walked for Betsey Johnson, Tommy Hilfiger and other top designers including Marc Jacobs, who said at the time, "We all just fell in love with her. We're expecting her to be a big star."

Everyone was. But two years later, "I woke up and wasn't getting jobs anymore," says Gerren, now 18 and a high school senior in Santa Monica. "I had a hard time coping," she adds quietly. The brief arc of her career was caught on-camera by filmmaker Darryl Roberts and can now be seen in his just-out documentary, America the Beautiful (see box).

Shot over five years, the film hints at what caused her downfall: At age 14 she shot up to 6 ft. tall and gradually filled out to a size 4. "In Paris," says Roberts, "they told her she was 7 cm [2.8 inches] too big" in the hips. (In one scene, a French agent sucks in her cheeks and chides Gerren to be "more like zhis.") "She started to hit maturity," says Klayman. "The clothes are the clothes, you fit them or you don't." Word spread that the girl hailed as "the next Naomi" had a "fit problem" and was shut out of Milan as well.

Did the industry reject a rising star for being too big? Or did other factors doom her career?

Though Gerren never looked her age, being so young was an issue. Flying her to a location meant buying a ticket for her mom, Michele, too. (Gerren's father, she says, has not been a steady part of her upbringing.) "When she was 13 they wanted to send her to Jamaica without me," says Michele, 48, a television editor. "I wouldn't let her." She sometimes demanded that more fabric be added to her daughter's runway looks. She nixed trips to New York if Gerren's school grades slipped. "Her mom never let income affect her judgment of what was the best thing to do for her child," says Klayman. "I have to respect that."

Yet, in an effort to advance her daughter's career, Michele left Klayman and signed Gerren with—then parted ways from—a series of other agencies. Unable to book shows in Europe, they returned home from a 2006 trip, with criticism about Gerren's size still stinging. "She started to say, 'I look ugly, my face is fat,'" Michele recalls. Gerren began severely restricting her diet. "I didn't throw up, but I'd eat, like, a piece of bread all day." She never became dangerously thin, but she and Michele did seek the help of friends at their church. And they stopped pursuing a modeling career (though she remains on Elite's L.A. roster).

"I realized modeling was such a small part of life," says Gerren, whose 6-ft., size-4 frame is these days an asset to her school volleyball team. And that's not her only extra-curricular activity. Since 2006, she's been on the BET hit Baldwin Hills, a reality show about a group of L.A. teens. "She's going to be big someday, one way or another," the show's creator, Sheri Maroufkhani, predicts of Gerren. "She has so many aspirations outside of modeling." But if the fashion world were to beckon again? "I would ask how much they're willing to pay," Gerren says with a laugh. "Because I'm charging. Those guys did me wrong."