Sometimes parents and kids don't realize it, but kids are going to be making a transition to puberty soon, and with that come changes that tend to sneak up on us. The biggest issue they presented on The Brady Bunch in the 70s was the time when Peter's voice changed. They even sang a song about it.
Autumn turns to winter,
And winter turns to spring.
It doesn't go just for seasons you know,
It goes for everything.