Most Helpful Guy
I'd say that the average guy matures in his late 20s/early 30s. Some obviously much earlier, and some later. Probably about half of women are reasonably mature adults by their mid-20s, several years before the men.
Most Helpful Girl
Never... kidding. It really depends on the guy, I think. Some mature earlier than others and it depends on what you call mature. I think people mature when they experience life - eg have you noticed sons of single mom's tend to mature quickly because they often become man of the house.