What does it mean to be an adult

To be an adult is to be in a older age and to be responsible for your self and it can also mean to be mature. It like my mom and dad they are adult and responsible for there self and they also mature they dont act like us kids they play but it a time when they have to be serious. Some day i would get to that age where i would be an adult. But for now i want to be a teenager because i want to live my life every second of the day. But in other case people say that im inmature. I really dont care because i want to be a playfull person until i really grow up and be ready for the real world ..