Dear Brother,
You are not alone. Whatever you are thinking now, you are not only the one to think so. Every teenager goes through the same shit you are into now. But that's not the end for you. You're stronger than you think you are, braver than anyone ever was. Stop worrying about what you are gonna be and start to live what you are. Be the better persona of yourself than you were the last day.
Never hesitate to get into trouble because that is how you learn not to make any mistakes. Brooding over the things happened is not going to help you in anyway. Instead, get over them, forgive those who have done bad things to you, be a helping hand to yourself, remember the pain you have been through, never forget from where you started and the people who were there for you from the very beginning.
Don't you listen to anyone who says you are incapable, how would they know what you are capable of? You are what you are and you will be what you want to be. Climbing the mountain of success isn't easy. You have to climb up the hair-raising steeps of limitations, bear the strong winds of criticism, survive the avalanche of humiliation on your journey. Remember to be strong, optimist and never yield.
Your future self