Son, some days you will feel like you are a sham, a fake. You will feel that if people knew the real you they would be shocked, or they would really like you or whatever... Jack, everybody is pretending. Or put another way they are presenting masks to the world. Everybody constructs this persona they want the exterior world to see. And within that more masks for those they let get close. And inside that the masks they alone see, because most people don't even face their own real self too often.
A great way to explore this and come to understand it at a visceral gut level is to do some mask theatre training. Go to amateur dramatic classes (you'll get that advice from me in several contexts) and see what an unsettling effect a simple mask can have on you and on your interactions with others.
Sadly the layers crumble away over time in a relationship and people get to see the real inner versions of each other, and it is seldom as pretty or cool or noble as the original image they had. Just as by now you will have got to know me and your mother better than you would have liked. I hope what you found is not too disappointing, but it is never as good as the polished outer mask.
But more to the point here for you as a teenager, I want you to understand that nobody is as cool as they seem. Even the most composed, unflappable, suave character at school is, inside, as lost and confused and winging it as you are. It is just some people get away with the sham better than others.
Every now and then you get a glimpse inside someone you thought was über-cool. You glimpse their face when they think they are alone. Or they get slobbering drunk, or they deal with some emotional trauma, or you share a campfire late one night somewhere, or you become lovers, and they spill their guts to you. And suddenly you see they are all as lost and confused as you. They are making it up as they go.
This knowledge, once you come to believe it, won't make you any better at shamming coolness, but it will make you feel a bit better to tell yourself it when some bastard out-cools you.