Dear 16 year old April,
The most important thing I want you to know is that God loves you! Really loves you! And not because you've earned it. Because you can't earn it. Even though you began your relationship with Jesus two years ago, you still haven't let that sink in. So spend these years learning about God's love.
I know you're already thinking about who you will marry and viewing marriage as a panacea. It's not! Instead of worrying about guys, enjoy your girlfriends! When the right guy comes along, he will pursue you; you won't have to make sure he notices you! When you are married (in just 6 short years!) you will never regret not having a high school boyfriend! Trust that God has good things for your future, so you can enjoy the good things He is giving you right now.
Learn how to live a righteous life without being self-righteous! Love the people around you, even if they were cruel or indifferent to you in the past. You are making so many right and good choices. Please don't look down on those who aren't. They need your grace, not your judgment. Realize the depth of God's grace to you, and it will be so much easier to give grace to others.
I know you feel so insecure. What you don't know is that most of the people around you also feel that way. So instead of worrying about impressing others, focus on finding your security in Jesus. He wants good things for you. And don't be afraid to let others see your need. Because trying to pretend like everything is fine and hoping that others will see through that and reach out to help you (and feeling resentful when they don't) is counterproductive! So let some people into your life. You are worth it!
Spend time with Dad without resentment. He is learning how to love you, so don't make it harder for him. I know he needs a lot of help; be patient with him.
Don't cut your hair! It grows slowly, and you'll regret it. If you go to your junior prom, go with friends, not a set-up date! Trust me on this!
Most of all, enjoy the moments God is giving you right now! Soon enough you will be at Baylor! But all the great moments of high school will be over. No more flag corps or high school football games or eating lunch in the band hall. So be thankful for now.
Your older (and I hope wiser) self