Now 58, the blonde beauty is aging gracefully, but confesses it isn't easy.
"I realize how artificial it is, beauty, I realize that it doesn't last forever, that's for damn sure," Derek told "CBS News Sunday Morning" on Sunday.
"Aging is really hard, and it's tough," she added. "Bette Davis was right; it's not for sissies, it really isn't."
Derek admitted she feels outside pressure to stay looking young, especially working in Hollywood.
"There is a certain expectation," she said. "I get credit on one hand for not having had a facelift, and then on the other hand it's, 'Oh my God, why doesn't she do something?' So you're just torn. I just have to keep busy, have other interests, and try not to think about it."
Derek mostly keeps busy on her 110-acre ranch in California's Santa Ynez Valley, which she shares with her boyfriend of 13 years, actor John Corbett, and their four horses.
She's also back working on the screen.
Derek will play the mother of actress Tara Reid in the third installment of Syfy's hit TV movie series, "Sharknado."
"It wasn't really acting," she laughed, when asked about the role.
"But being on a set, I love the business, I love the film business. And it's always been good to me," Derek said.
She added, "I don't need a lot. I never needed the adoration or the praise. I loved the work, and still do."