Kids? Teens? Adults?

There is a lot of conflict and confusion by being defined as an adolescent. The article we read about adolescence showed the idea that society puts us in a crazy state of being because were not children, but were not yet adults. But we are adults biologically in many ways. There are some things that we are given the opportunity to have adult status and not others. Some examples of the things we are given the opportunity to do is driving and getting jobs. But even with that we are still treated like kids. When we drive we have to get hours and once we get our licenses we have rules like having one person in the car for a year. When you get your license when you are 18 you dont have to follow any of those rules. When your 18 you can get a job. But when your under 16 you need a workers permit. There are other things adults do that we cant. aka drinking and smoking. at 17 you have many adult responsibilitys and then at 18 you can smoke. But even when society sees you as an adult you still cant even drink until your 21. So when do we actually become adults? At 18 is when society sees you as an adult and legally you are an adult. But there still isnt things you can do. So really what is the timline between being a kid, a teen, an adolescence and finally being an adult?