She’s 63 years old, a mom of one, a published author and an Onset resident. Oh, and she’s a bodybuilder.

Dr. Mimi Secor may not be your average bodybuilder, but she is dedicated and wants to share her knowledge and experience with others in her new book, “Debut a New You.” She didn’t get seriously into fitness until three years ago, when she became overwhelmed with stress.

“I didn’t take care of myself when I was stressed,” Secor said. “I wasn’t being a role model to my patients or to the community.”

But she found that when she lifted weights, at her daughter Kat’s recommendation, the stress melted away. She lost 30 pounds and 12 inches off her waist.

“I felt better almost instantly when I started lifting weights,” Secor said. “All my aches and pains went away.”

Some people think it’s too late in life for them to get healthy, but Secor said she’s living proof that it’s never too late.

“The inevitable decline of aging is not inevitable,” she said.

But, she advised, older people are more at risk for injury in the gym, She recommends asking a trainer to demonstrate how to do the exercises properly. As long as lifting weights is done safely, she said the health benefits are enormous.

At her second bodybuilding competition, the NPC New England Championships in Boston, Secor came in second place in the over 50 category. It wasn’t easy: she spent eight months eating pure protein to trim her legs down and she only ate carbs on Saturday nights, usually Marc Anthony’s pizza. Mostly, she ate egg whites, chicken and vegetables.

Secor, a nurse practitioner for 40 years, has published two textbooks, but her new book is more of a how-to guide to improve exercise, nutrition and mindset. Mindset is more important than people think, she said, calling it “cleaning your inner house.”

“It’s not a weight loss book, it’s about changing your life,” she said. This grows confidence and success in addition to muscles. It is an introductory book, focusing mostly on making small changes to daily habits.

What about New Year’s resolutions? Secor said setting huge goals can be overwhelming and recommends making little changes: drinking water, setting aside time to go to the gym.

“A little planning for your day can make a big change in your life,” she said. “People need to not give up on their dreams.”

Secor’s rule is to schedule everything.

“You cannot wing a healthy life,” she said. But her book also emphasizes the power of “imperfect action” and not feeling pressured to get everything right all the time.

“Debut a New You” sold 700 copies on the first day all over the world. It is available from Amazon.com or at www.debutanewyou.com. Secor welcomes questions through her Facebook page, Coach Kat and Dr. Mimi.

Secor will have a book signing at the Wareham Public Library on Dec. 28 from 4 to 6 p.m. Her book will be available to purchase for $20.