Is it true that the 20's is where you learn who you are and make most of your mistakes?

I am in my 20's at the moment. I feel like the last year especially has been a huge learning curve. I have really been reflecting on who I am why I do the things I do. Why I did the things I did in my past etc... It also means that im faced unresolved issues that has made me do and say things I would preferred not to have said. When I know deep down im not that kind of person?