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? 
You can get through it all
It's not you.
Dearest,
When you are young, you should be wild. Enjoy childhood as it is. Make memories with your friends. Do silly things but remember to use your mind all the time. Boys arent supposed to be in the scene yet. Be childish. Be vigorous. Take time to talk and play with your siblings. Be open to your parents and develop a close relationship. Don't think of romantic relationships. They will come when you too are biologically ready. Be a child. Seek out friends. High school is supposed to be fun. Learning is within and outside the four walls of the classroom. College is to prepare you for your career you want to take. Take it a lil seriously. It may seem difficult but Im sure you'll look back and say damn it was just that easy, had I given it time to read and understand! Have mature talks with friends. You'll see how much you've grown. Flirt with guys. Flirting can be fun and exciting. But now your boundaries.
In a nutshell, don't rush things. It will all fall into place. I wish I didn't rush some things before.
@CRISPR my typo with the NOW: should be KNOW
You are Awesome
I thought of two. "Yes, you're gay" and "It'll be okay."
Never change for anyone. Spend as much time as you can with your mom and dad
Make sure everything you're doing is fun and something you enjoy. Put a good twist on everything. Don't be afraid to be yourself. Wear those wacky clothes that are weird to everyone except you. Love your body you will eventually grow into it. Respect yourself and your mother. Don't be afraid
I would love to say Take care, that's only two words, but it pretty much sums up what i want i mean :)
It gets worse, but then it gets better (I know it's more than three words don't yell at me)
Always work hard