Growing up

Even though I have graduated from college, I still have a lot of work to do in order to become what society deems a 'grown up.' I'm currently working for basically minimum wage at Walt Disney World, where I suffer to make ends meet. There is a huge part of me that needs to get to that maturity level of having a real job and acting as if I were an adult, but there is such a huge part of me that just wants to go out and play all day long.

Why is there such a stigma on growing up? Why do so many people (mostly young people) look at growing up as a sign of giving up? Why can't I find a comfortable medium where I can both be mature and a kid at heart, and still have society accept it?

But then again, when did I ever care about what people thought about me?