Christian makes a joke

*In the car, driving around town*

Christian: "Daddy, when I'm 17 I'm going to buy a whole bunch of random stuff."
Me: "Oh, really? Where are you going to get the money to buy that random stuff?"
Christian. "I'm just kidding. I'm not going to spend all my money. I was making a joke."
Me: "Oh. Are you going to have money to spend when you're 17?"
Christian: "I'm not going to spend it all. I'm only going to buy what I need and then I'll save the rest."
Me: "When you're 17?"
Christian: "Yes."
Me: "Where are you going to get all of your money when you're 17?"
Christian: "What do you mean?"
Me: "Are you going to have a job?"
Christian: (sounding incredulous) "Yes. Of course."
Me: "OK, that's good."
Christian: "I'll be working from home."
Me: (surprised) "Really? What kind of job are you going to have at home?"
Christian: "Chores. Duh."
Me: "You're going to make enough doing chores to buy everything you need and save money?"
Christian: "Yes."
Me: "Haha... Now that's funny."
Christian: (has no idea why I'm laughing)