Development Tracker of 4 years old

Hello everybody? I am wondering what is the expert say about 4 years old so i search online. I found this information from
Parenting.ivillage.com:

They move at the speed of light, racing up stairs, dashing off on bikes and trikes and sprinting from one end of the house to the other. Your relatively calm 3-year-old has grown into a firecracker. On occasion, his demeanor -- boisterous, bossy and belligerent -- may remind you of those turbulent toddler years. But fear not. This difficult period is usually short-lived. And by the time he arrives at his fifth birthday, he'll be calm, collected and brimming with self-confidence.

Now i know why my son act this way. Hope this information will help you understand about your kids. See you.