An award-winning journalist tells the inspiring story of her unlikely midlife journey to master the daunting sport of obstacle course racing—a powerful, science-based account of the change possible at any age when we push limits.

“This story of personal transformation is thrilling.”—Gretchen Rubin, #1 New York Times bestselling author of The Happiness Project and Life in Five Senses

In her midforties, Gwendolyn Bounds attended a dinner party where someone asked a little girl: “What do you want to be when you grow up?”

It struck Bounds: In middle age, no one asks you that anymore. So she put the question to herself. The answer set her on an unexpected five-year path of transformation from an unathletic office executive glued to her screens to an age-group medalist and world championship competitor in obstacle course racing—a demanding military-style sport requiring speed, endurance, mobility, and strength.

In Not Too Late, Bounds explores how tackling something new and hard upended her expectations for middle age—while also helping her reconcile regrets of her youth. Her story takes us from playgrounds and gyms, where Bounds relearns childhood movements (swinging from monkey bars, climbing a rope); to far-flung Spartan Race courses, where she strives to master running in difficult terrain and to conquer challenges such as scaling tall walls, crawling under barbed wire, and carrying heavy loads of rocks up mountains.

Bounds’s journey offers inspiration and a road map for anyone craving more out of life. Woven through Not Too Late are insights from scientists, longevity doctors, philosophers, elite athletes, and performance experts on how to reimagine our limits and who we think we are. Through Bounds’s story, as she changes her body and mindset, we learn about humans’ capacity to tap inner reserves, face fears, locate intrinsic motivation, and push boundaries at any life stage.

Ultimately, one message prevails: When unleashing our full potential, age can be a secret weapon.