because medically speaking woman mature at a faster rate then males do, but you are correct in thinking that people also need to consider outside influences when talking of maturity, because they may be phsically more mature then a male but some females aren't mentally mature at the same rate
You appear to have made the mistake of taking the generalization of male vs. female maturity and tried to make it apply to every case, or otherwise falsify it because you can think of cases that don't match. SexyCrystal and Regular Guy are right, women mature physically and intellectually just a few years ahead of guys. And guys in their teens and 20s tend to do more risky and stupid stuff more than girls (who also do their fair share, but less). I am not saying all girls are mature and all guys aren't, just that on average girls are more mature than guys, behaviorally and otherwise.
Well first off your statistics are probably based in your local area.
Secondly - men have a tendency (speaking of the average "guy-who-gets-the-girl") to go out to parties/be social/drink/etc... While this is more commonly seen in the "bad ass" the "player" and the "womanizer" groups of men, it is also common for some people outside these groups.
I don't like getting into stereotypes so ill stay away from that.
These guy's are more concerned about being popular and having lots of buddies to go do stuff with; woman are approached day in and day out by thousands of men - either in forms of compliments, or potential dates. As such - women have more focus academically to do what they need to "set their life" with the best foot forward.
=/ This is just my opinion which seems to apply in my local area. Keep in mind there will always be different women and different men that are outside the "statistics" range - in which case you can't classify them into such a generic questio =)
It's just the way it is. Women mature physically and intellectually more quickly. And while girls often do plenty of idiot things, they would seriously have to kick it up a notch to catch up with us guys at the same age. Guys tend to engage in more high risk activities, and girls tend to be a little better about being outward focused and more willing to serve and help. I am not talking about universally, just on average.
"Keep in mind the average young female lives at home until they are 25 and don't get their first job until 18"
Bad statistics are bad. Every girl I know is away at college working multiple jobs, and have worked said jobs since 16. Besides, they are considered more mature because guys in that range are usually horny bastards obsessed with sex, or they are typically assholes. There's plenty of reasons why they are considered more mature.
But I honestly believe its the same between girls and guys since I also know a lot of flaky immature brats.