That’s how it was when I grew up, as well. I now know adults in their 30s with a part-time job, or no job, still living in their parents’ house - and the parents re completely fine with it. There seems to be no expectation that the “kid” will take a regular, full-time job.
When I turned sixteen, I was expected to have a full-time job for the remaining high school summers, and then summers and semester breaks in college. After that, I was expected to get a job and rent an apartment - sharing if needed, a room in someone’s house, whatever - and support myself.