Um, How old are you again?

So my mom may not want me to spread her business, so I won't. I will just ask, why do adults act so juvenille? I am sixteen years old and all my life I have been put down by older people. They all tell me that I am not as capable of thinking for myself and making good decisions as they are, simply because I was born a few years after them. I think I am smart and mature for my age. And I also think that everyone is just as capable of screwing up as I am. So what I want to know is, at exactly what age are people suposed to be considered "grown up"? Is it just an age thing? I don't believe it is. I think you mature as fast as you want and you learn everything you know from experiance, plain and simple. I think everyone is the same when they are upset or feel strongly about something, and I think everyone is the same when they want to do bad things to purposely hurt people. It doesn't matter how old you are. It is so stupid what happens to people when they don't get their way. No matter how old, they all become whining toddlers, banging their head on the floor and screaming until someone finally gives them what they want. No one can get what they want all the time. It's not possible. Everyone needs to be told no once and a while, including myself. If something doesn't go your way, deal with it people! Don't blame your race, sexuality, age, religion, weight, etc. Sometimes things just don't happen in your favor. What I don't understand is why all the adults keep telling me to grow up when most of them turn into children when something COMPLETELY STUPID makes them a little upset. Everyone wants someone to blame and take it out on, and they don't care how it will effect that person. And as for social status? WHO CARES IF YOU HAVE 5 FRIENDS OR 50 BILLION?! The truth is, no one is completely honest and trustworthy, and you don't really know who your true friends are until you need them the most. Everyone has always told me that life isn't fair. I have learned that on my own, and I think it's about time all you spoiled toddlers out there do too.