My biggest thing I would stress 'young' self is this- your life is going to turn out entirely different than you could ever imagine. Some really incredible, wonderful, amazing things will happen. Chapters of your life are going to be filled with joy, filled with laughter, filled with love, and filled full of wonder. But, with those good incredible chapters, your life will be filled with sadness, despair, tragic turns and events you won't see coming. You will fall. You will be knocked down. You will struggle and feel like you are drowning.
But, you will always get up. You will keep smiling. After those really terrible chapters, light starts coming again. Laughter finds it's way back in. You will find joy and peace again.
Despite the bad, you still will have a good life. You have been blessed. Very blessed. You will cherish and appreciate the smallest things.
God is good.
You need to own your life. You need to own it all- even the very bad chapters.