Dear 16-year-old Grady,
First of all, hey! You are cute-as-a-button and you don't even know it. Which is your first problem. You are NOT "the fat friend," that's just ludicrous, so get over it and start cultivating your awesomeness. I promise you, once you realize your potential - and start trying to figure out how to live in that potential with humility - you'll be unstoppable.
But you know what? Despite all that, you're still going to fail. You're literally going to make at least one mistake every single day of your life. Sometimes the mistakes are as tiny as forgetting to bring that book you wanted to read and sometimes they are as massive as saying something seriously hurtful to someone. Always strive to improve, of course, but also remember that there's no shame in making mistakes. And being so afraid of messing up that the only action you ever take is inaction? THAT is a mistake you will remember for a long, long time.
Just so you know, you don't talk to most of your old friends from high school anymore, and that's really okay. You don't need to feel like your life is over every time you get into a fight. The people who you belong with, your people, they are still around. And that group has grown exponentially, so don't worry about trying to be best friends with everyone from school. Proximity does not always equal friendship.
Grady Katherine, you are a force. I think you know it a tiny bit now, but trust me you will know it all the more as you allow yourself to care less and less about what others want for you and more and more about what you and God want for you.
There is so much more that I could say, but I wanna leave a mystery or two for you to figure out on your own.
Oh, wait! Two more things: Pajamas are not real clothes and your mother is almost always right. Even on your worst days, try to remember both.
Love you always,