From one child to the next in my family there are marked differences in the way they respond and play. The younger ones may spend a great deal of time entertained by pulling around a small toy. At a little older age, hours are taken in play-acting. As the children age, their taste for fun usually changes. Thirteen year old Nathan can spend hours inventing something or making some gadget to fulfill a perceived need.
Youthful immaturity is entertaining except when found in someone older.
When someone doesn't mature, there is something wrong. To each he had a word of encouragement and explanation as to why he had addressed them. He didn't disparage that all were not mature. It is sad when a Christian doesn't mature. You should be until the day He calls you home.