What does it mean to be a kid at heart?

Hey Diddle, Diddle
Here’s a great riddle
When do we stop being kids?
Let go of your dreams
And stop having fun
And life will go into a skid.
The man in the moon
Came down to soon
Because he was feeling his age.
He said to the cow
There’ll be no jumping now
I’m tired of you acting so strange.
The dish and the spoon
Went into a swoon
‘We’re never too old to play’.
The cow gave a moo
Said, ‘I’m so sad for you‘
There’s no time for fun in your day.
The little dog groaned
‘You aren’t any fun’
Ran off with the dish and the spoon.
You’re never too old to be playful
It’s sad to be grumpy and dull.
Age is partly a mindset
I want to stay child like for now.