Tiffani Thiessen Feels Better at 50 Than 40, But She’s Still Dyeing Her Hair: 'Not Ready to Go Gray' (Exclusive)

Tiffani Thiessen, who recently celebrated her 50th birthday, has no problem with aging — especially since she says she feels physically better now than she did a decade ago.

"I was way more nervous about turning 40," she tells PEOPLE of entering her 5th decade. "I think because in my 40s, my focus was still on my children [Harper, 13, and Holt, 8.] Also there were still a lot of bodily changes from pregnancy, hormones, that kind of stuff. I wasn't able to really give myself any time to put into me."

Now that the kids are older and in school full time, she says she was able to focus on her wellness a little more. "I was kind of prepping myself to turn 50, and really wanting to look and feel the best I could, whatever that means. So I feel good," she says.

She also puts in the work. "I'm a huge gym rat," she admits. "I work out a ton. And I'm very much into ice bathing. It's so good for you. I'm obsessed with it. But it's hard. I put it right up there with natural childbirth. Ice bathing is a huge mental challenge."

Thiessen has also long prided herself on eating organically, and even grows her own vegetables and keeps chicken in the yard for fresh eggs.

"I always gravitated toward that lifestyle," she says of urban farming. "It's how I was raised. We always had chickens when we were little. My dad worked for the city of L.A. designing all the public parks, so he had a green thumb and we grew a lot of our food as well. I wanted to do the same with my children. Luckily my husband was on board too."

Of course, the Saved By the Bell alum admits there are some challenges with turning another decade — including thinning hair, which is why she says she recently partnered with Nutrafol, the all-natural hair growth supplement also beloved by stars like Jamie Chung and Alyssa Milano.

"There are no drugs, it's all natural, which is very important to me," she says. "Just putting extra vitamins and things that are good for me into my body made sense."

Thiessen says she's already noticed way less shedding and stronger locks. She also says having thinning hair was especially tough because she'd grown up in front of the camera as someone who was famous for having long thick hair — everyone knows the Kelly Kapowski mane — on her her hit '90s show.

"A lot of people always focused on my hair," she says. "So it's important to me that it looks good. Also, your hair health show a lot about your health in general. But you can't help the hormonal changes that happen with pregnancy and age."

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As for whether she'll embrace her grays? Not yet.

"I totally cover the grays," she says. "I have no embraced it. But my mom just went completely grey and did the whole transition, and she looks so good. So I'm like, Ok, maybe I'll get there."

She adds with a laugh, "One day. Maybe."