Our November cover star Jillian Michaels has had a whirlwind year.

The celebrity trainer made headlines for being visibly shocked at the dramatic weight loss of The Biggest Loser season 15 winner Rachel Frederickson, and shortly thereafter rumors started swirling that Michaels wanted to leave the show. She did so in June, marking the third time she split from the reality competition program. She also launched an activewear line with K-Mart and has been expanding her workout streaming site, FitFusion. All this after turning 40 in February.

In her refreshingly honest interview, she spoke with Health about her milestone birthday and the sense of calm that came with it—for which we assume she is very grateful.

"There's a confidence and sense of self that comes with age that I didn't anticipate," Michaels said. "I don't feel the need to prove myself now, which I did for a very long time. And there is a peace that I didn't have in my 30s. I no longer feel this urgency to make impulsive decisions."

And as she told us in her candid cover shoot video (above), her fitness motivation has evolved, too.

"In my 20's, I was inspired to stay in shape for skinny jeans and the two piece. Now it's really all about my family. I really do want to be that healthy, active mom that can set a good example for my kids," she said. "And, of course, continue to wear the two piece instead of the one piece."

Want more Jillian? Check out her full interview and try her new 7-move workout for Health: Jillian Michaels' Total-Body Shred.

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