From a Washington Post story by Matt Viser and Adriana Usero headlined “On his age, Biden is now trying to show he’s in on the joke”:

Joe Biden once joked that, when he knocked on doors while running for senate as a 29-year-old, people would mistake him for a newspaper delivery boy, or perhaps someone wanting to cut their lawn.

The crowd laughed.

As a 44-year-old running for president for the first time, he was introduced as the “young fella” — someone who could speak without cue cards and teleprompters — and then stood before his audience and declared: “My generation is poised to respond to this challenge.”