What is the age by which in general terms kids "mature"? or become responsible?

This is a tricky question. I believe I started to feel like an adult in my thrities. But, I was kind of born responsible. In terms of being responsible for paying my own bills, living on my own, and earning my own living, that happened after college. But, in college, even though my parents funded it, I had to be responsible with the money. I started working at 14, so I held a job, and was a great sales person, competing with the older teens working there.

I think 28 for me.

According to most things I have read, the brain stops growing around age 21, so one would assume that it could coincide with that.

I’d say 28 for most….I think by that time we’d get tired of all the alcohol, parties, and drugs..lol…

I can’t speak for everyone but much the same as @JLeslie I was earning my own with two jobs at fourteen. I left home at sixteen & moved into my first flat….

I think that it depends a lot on how a child/teen is raised and what responsibilities they are given. if a child/teen is held accountable for their own actions and realizes that there are consequences for them they tend to step toward adulthood earlier.

This is so varied from person to person. Some people really never grow up or are a person I would want to assume as responsible.
One might argue on an age or a level of education I guess.
I have come across many a person at each decade that still doesnt get it, or has times where they do things that are not mature or not responsible. Does that make them generally not mature or responsible?
I have also seen pleanty of teens that are mature and responsible well past their years.
If you are talking generally mature and can make sound decisions, one would hope by 21 or after 4 years of college. That is however a wide sweeping generality. On the other hand as far as being responsible, that may fall in line also with 21 but generally at an earlier age than 21.
am i being irresponsible or immature for being on fluther when i should be working?

that question shamed me back to work

As others have said, it completely depends on the person. There is no age of maturity.

It depends on when the person takes responsibility for their own life.

Some people NEVER grow up, others seem to have been born that way. It’s largely genetic, I’m afraid.

I think that it’s around thirty, plus or minus. I think that kids can also start to take on responsibility at a very early age. Around the age of ten or twelve, you can start trusting them to think about the consequences of their behavior over a longer period of time. That means they might make better decisions. Between ten and thirty, though, there is a lot of maturing to do.