At least for a gamer like me, this "maturity" is for people over 18. If a game is rated M (for Mature), then only a person 18 or above can buy it. But do maturity grow alongside with age? Do all people who are at least 18 are matured? Of course not.
According to TheFreeDictionary, mature is defined by "Of, relating to, or characteristics of full development, either mental or physical." If we are going with the definition, then certainly we can see that age does not really confide our maturity, especially on the mental part.
I don't really have a lot to talk about maturity, at least when viewing at myself. I know I am 20 this year, but I never feel like I am mature enough. I can never say that "I am matured!" to everyone since there are always some parts of my mental and thinking skills that haven't matured enough.
A few people I know always care too much about maturity. They can even declare themselves of being mature to others. I know that nothing is wrong with that IF they are truly mature. But don't you think that we don't really have to say that we are mature for others to realize it? Maturity is shown rather unconsciously. Plus, why need to show your so-called maturity? You make yourself look more pathetic.
To be honest, I hate people that deal too much with this "maturity". They talk about it, they try to define it, they tell others, but in the end they ended up being more childish. To make themselves more "mature", they judge people and then decide whether they are matured or not. Don't you think that is proof enough that you are childish?
If you want maturity, then stop thinking about it too much. I know a friend of mine who is really matured but don't have to say anything about maturity. In Madison, there is a friend of mine that is really matured. She doesn't has to brag about her being matured or not. You can see how she manage herself diligently. I don't know how to define it more clearly, but if you hang out with her, you somehow feel that she is older than her age is.
There is no exact way to prove that you are matured, but at least don't freely decide who are matured or not. You, who can't even take a word from others, want to call yourself mature? You, who always want attention of others, want to call yourself independent? You, who can easily get upset by even the smallest matter, yet still want to justify that you are matured? Know your place.