Finally Understand What's Going On Inside Your Child — and Navigate Puberty Prep with Confidence (Ages 9–12) Does your child suddenly seem like a different person? The mood swings, emotional outbursts, eye rolls, and resistance — and you're not sure how to respond without making it worse? You're not alone — and you're not failing as a parent. Between ages 9 and 12, something profound is happening. Your child is entering the preteen years: the critical developmental window before puberty when kids begin testing boundaries, seeking independence, and navigating real challenges like peer pressure, social media, and shifting friendships. Whether you're parenting boys, girls, or both, this phase demands a whole new approach.