There’s a special kind of happiness found in the playground — the pure, unfiltered joy of running, climbing, and playing without a care. But as the years pass, that boundless energy naturally gives way to a quieter kind of strength: grounded wisdom. The secret to truly embracing both? Starting early. When I was 14, my neighbor Jason used to wave to me from his porch while his two young kids ran circles around him. He was in his early 30s — laughing, chasing them, and somehow still had the energy to run and jump about in the playground. One day, he said something I didn’t fully understand at the time: “I’m glad I started early. I still have the knees for this.” I laughed, thinking it was just a joke about aging. But a year later, I began to feel the tiniest signs of my own body slowing down, and his words hit me differently. I found myself wondering: Why not start having kids earlier? Having kids when you’re younger isn’t about “getting it over with” — it’s about having the energy,...