Of course, in show business, she's one of the winners. The star of TV's legendary "Beverly Hills 90210" has conquered her toughest challenge yet - comedy.

"That was a big step for me," she says, looking rosy-cheeked in the afternoon sunlight.

"I kind of went out there on a limb. That was, I think, the hardest thing I've ever had to do. It crossed my mind at times that I couldn't do it. I had to just shove that aside because that was not going to help me through it," she says.

"I think it was the perception of everyone else that was scaring me more than anything. But once you did it, and everything went smoothly, those fears sort of subside till you have to do it again," she says with a grin, running her fingers through her straight, blond hair.

Garth, 30, is starring in her first sitcom, "What I Like About You," airing on the WB at 7 p.m. Fridays. And to everyone's surprise (even hers), she's amazingly good with physical comedy. Of course, her gentle demeanor and soft-spoken delivery have always masked a dogged determination that saw her emancipated and performing professionally at 16.

Today, pregnant with her second child (due in December), she calls herself a "late bloomer," but it's clear that Garth grew up quickly.

"My father was sick when I was about 13 years old. He developed heart disease and has been sick ever since, but he's still tickin'. . . .

"It sort of ended my childhood at that point and changed the dynamics of my family a lot. And we had to be uprooted from our home, and it changed things on every level. We were in Illinois (Urbana) at that time, and we moved to Arizona (Phoenix) for the warm climate for him," says Garth, whose gushing note about Tucson's Maya Quetzal still hangs on the Guatemalan-food restaurant's wall.

"We had to separate from the family . . . so that was a really traumatic time - let alone watching my father go through that. That was tremendously life-altering for me and for every member of my family."

Garth has four sisters and two brothers (three of the siblings are half-sisters). It was her agent, Randy James, who first convinced her that she should leave Arizona to try her luck in Los Angeles. "He put the bug in my mom's ear and my ear, and we just said, 'Oh, what the heck,' " she says with a shrug.

"I'm not a planner. I didn't have anything that was disrupting. I wasn't really loving my high school experience, so. . . . I was really smart, but I wasn't applying myself. It wasn't going well, so I got my GED, and we came out."

Even though she played the comely, rich co-ed in "90210," Garth says her own high school years were not "Happy Days."

"I liked school; high school didn't like me," she recalls. "I had some peer pressure, girl problems, that sort of normal stuff that I pray and hope my own daughter doesn't have to go through. Girls can be so vicious."

Garth and her second husband, actor Peter Facinelli, have a 5-year-old daughter, who was 3 when they were married. They met on the film "An Unfinished Affair," which she produced. It was love at first sight, she confesses, adding quickly: "It was probably lust at first sight; then he opened his mouth, and I was done."

When they met, she was in the middle of "90210" and finalizing her divorce from her first husband, Daniel Clark.

"I met my husband (Peter) at a challenging time in my life, and that sort of just changed everything around," she says. "And it hasn't all been peaches since then, but it's certainly been good growth, as opposed to the road I was on before. I was in a bad relationship and was not sure which way was up at that point. Things were not . . . it was not a great time in my life. . . . He's been like an angel, kind of."

Even though she's suffered doubts in the past, it never seemed to stop her. "I'm really a confident person, that carries me through," she says. "Even if I were to fail, I would remain confident on some level. I do think that fear is a good thing, it keeps people going and keeps people reaching for more. So if there is a little fear mixed in with the excitement and anticipation, that's not a bad thing."