Right now your at the point where you start to realize grown up things, but honestly you could probably say more things are uncertain than you confidently understand. Between now and 23 you'll gradually notice you suddenly seem more grown up in phases, then then probably beyond but I can't say cause I'm not there yet. You'll start to really feel like an adult once you gain the confidence that it doesn't matter that things are uncertain, just work towards them and it will turn out okay. As you get older things will just suddenly make sense that you were so confused about before due to personal experience and more time spent thinking about whatever it is.