person A: When my nephew's car broke down and I loaned him my car_comma_ I know that he'll be careful with it.
person B: Well at least you can trust him to be careful.  I dont think I would be able to trust my nephew as he is only 18 and not very responsible yet.
person A: Yeah_comma_ 18 is an inherently irresponsible time_comma_ mine is 24 and getting married soon so that makes a lot of difference.
person B: Yes its amazing how much of  a difference a few years can make in age.  It seems that males take quite awile long to mature than females.   
person A: The culture that extends adolescence deep into their twenties doesn't help much either. 