Oh goodness, so many people feel like that at least some of the time - certainly, many (most?) teenagers feel like that at some point, and so do many adults! And, honestly, if CC makes you feel that way, that you should spend less time here. Don’t seek out things that you know will make you feel bad. Why? Find the things that make you feel good. That may mean staying off of off college forums or social media or wherever you often feel self doubt creeping in.
Of course you are good enough. You are more than good enough. As I said above, find something that makes you happy and do a lot more of that, and a lot less of doom scrolling forums that end up making you feel bad about yourself. Life is too short. And your future is every bit as bright as you make it.