What's 17 More Years?

Alright, listen up, buttercup. This joke is about a dad whose son just came out as gay. The dad's response, "What's 17 more years?" implies that he's not exactly thrilled and is dreading the next 17 years until his son potentially moves out or becomes independent. It's like he's serving a sentence, which is a tad insensitive but hey, it's a joke, and you clearly need it spelled out because you're denser than a neutron star.