You were born into a family of all boys, and grew up almost like an only child--don't feel bad about all the time you spent playing alone--it has made you value friendship very highly.
Don't worry about the fact that you have so much to say. There will come a time when you will need to speak up for the children in your home who "have no voice of their own."
When you marry young, and some people criticize you for it--take their advice and "think about it", but in the end follow your heart. Your marriage will be one of the best decisions you ever made.
Don't feel ashamed when your dream of becoming a nurse doesn't work out. Your life's vocation will include a lot of caring for sick children.
Infertility will take you by surprise and bring you to your knees, but for the rest of your life there will be others walking the same road that you can encourage.
You will stumble and falter at times, but you will pick up the pieces and go on. You will need to go back and say "I'm sorry", but this will only serve to make you stronger.
When you look at others and are tempted to compare yourself remember "I am fearfully and wonderfully made;"
You are unique, your life has a specific purpose, and no one can fulfill that purpose, but you.
Sometimes we are pretty hard on ourselves. We look at our past, and our mistakes and we see all the failures. This idea of writing a kind letter to myself is not original to me. Go visit here to read Betsy's version of it.