People learn this at different rates and for wildly different reasons. When I was out of college working at Amazon, I would be amazed that my colleagues seemed to lack skills like doing the laundry.
But I got kicked out of my home at 18 and it was made abundantly clear from the age of 16 onward that this would be the case. Remaining a child is a luxury that I wish everyone can experience for as long as possible
I draw the line at the point when someone has a stable job that allows them to pay rent. I've seen people who basically had "two youths" and they were generally unhappy.
we had to help with housework as soon as we were teens. laundry, shopping, cooking, dishes, cleaning the house. i didn't live alone until i was 27, but i had all the skills needed to take care of myself. staying at home was not laziness, but simply economical. i moved out when i got a job in a distant location.
A guess opinions vary. Remaining a child felt like more of a punishment than a luxury.
I wasn't kicked out of my home but I had the good fortune of attending a boarding high school starting at 13. This forced me to grow up and take responsibility, while still having limited adult supervision. I wish more teenagers could have that opportunity as it helps to provide a gradual transition into being an independent adult.