I've also found the definition of mature to be quite fucking warped these days.
When most people discuss maturity they're talking about pragmatism. They're talking about getting your head out of your arse and start thinking about things you think matter. Not even that, it's about what is directly relevant to your physical existence at this moment in time. Now, before I go onto some rant about time/existence (you can check a thread about 'now' in PSS for discussion on that) because that isn't the topic, so I'll digress.
Now let me preface any further discussions by saying I fucking hate 'maturity' in this context and I'm so glad there are 'immature' people in the younger generations. It's so ridiculous when I talk to many old people as they talk about the weather and work and other stupid small talk. Now, this isn't to say other people don't engage in mindless small talk, no not at all. Old people grew up in a different time, they didn't have the internet, or movies, music was less popular, work started earlier, etc. I mean I wonder if you, yes you, whoever the fuck it is reading this, will be old. You'll have no social life, you'll do less, are you going to be more mature? Are you going to start talking about the weather, the newspaper articles, your pet...
Anyway, what I'm trying to say is, 'maturity' is just a limit of what people think about, but more so, what they feel. You just focus all of your attention, you're so fucking concerned with what you call 'life', what you've made important and hold dear, that you miss all the fucking good shit.
It's like when you're a young child, you're so curious, and you question everything. You ask simple things that are commonly known, so your parent(s) answer you. This curiosity doesn't die, no, you're still left feeling like you don't know enough. You continue to question, and then you get a little bit older. Eventually you become an adult, and you're still ignorant, you've just changed priorities, you've lost curiosities. As you get older, this feeling remains. Nobody really knows anything, we're all just little kids stumbling around in the dark with our parents clothes on trying to act 'grown up'
Well fuck that
We're always going to grow and change, and 'maturity' as you so call it just impairs such growth. It closes your mind.
Fuck maturity, go take some drugs and listen to some music or read a book. Whatever, use your imagination. Seriously, actually be creative, imagine scenarios like you were 8 again.
Maturity is a cancer.
You can keep feeling like you understand so much, and like you're in such control... I'll just be over here with my eyes closed nodding my head along.