If you could write a note to your younger self, what would you say in only three words?
I had two thoughts. 1) Words can hurt. 2) Try your best.
What would your note say? 
Believe in yourself
You're going to be alright. Breathe it in and then let it go....
Stay away from technology
Do Your Best x
You Won't Understand
Don't care about what people think, and don't stress out about the future. Things will fall into place as they're supposed to be. And you're not supposed to have everything figured out in one day, figuring out things as you go is the fun of it. You're allowed to make mistakes, and be young and stupid. It's completely normal to fail at certain things. Have faith in yourself, and know that everything will be okay. Everything in life is either a blessing or a lesson, things happen for a reason
Never grow up!
Follow your instincts
It gets better.
Just slow down