I honestly don’t even know what generation you’re assuming I’m from and referring to. Is this supposed to be something old people don’t understand? Or young people?
Of course you can have standalone jokes, but “I’m six years old” is not one.
It’s not a generation thing. The joke is the OP is obviously not six. We know that because most six year olds can’t come up with such an artifact to set the timeframe of an article. For more references on jokes like this read MAD. ;)
Could you give an example? Even puns stand on aspects of language to acquire their potency.