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

I have heard its after college
I have seen people mature at many different ages

Is there a certain age by which in a general sense people mature? or are responsible to some extent?

At what age does the kid or adult actualy become an adult? and by adult I mean responsible in every way possible. (towards others, for himself)

There may have been an age traditionally, but it may not exist today due to people’s lives being so open and connected etc