"I wish I was normal!" Kevin said.
Suddenly, all across the world, things began to change. Kevin's wish was interpreted to mean he wanted it to be normal for 17-year-olds to be considered babies. Across the world and through history the changes were made. People were now considered babies until they were 20. Kindergarten now started at age 23, and high school ended at 38. To accommodate for this, people live a average of 20 years longer and don't age between ages 18 and 38.
4-year-olds in parks suddenly were replaced by 22-year-olds, and the playground equipment grew larger to fit them. High school students are suddenly in strollers, high chairs, and cribs instead of desks. Middle schoolers no longer eat school lunches, instead living off of formula and breast milk. All major diaper brands offer sizes for babies up to 20 years old, and pull-ups for potty training 21-23-year-olds. Anyone under age 12 is basically a newborn, unable to even roll over yet.
All of history changed to fit this new reality. Due to a much higher demand for diapers, disper companies invented disposable diapers decades earlier, and have now invented diapers that biodegrade rapidly to help the environment.
Kevin has doomed himself to a baby's life.