I’m very thankful you have given your life to Christ; it’s the most important decision you will ever make. I’m thankful, too, that you’ve made your decision while you’re young. The older we get, the harder it usually becomes to hear God’s call.
The most important thing you can do is to learn to walk with Jesus every moment of the day. You are not alone as you walk the halls of your school, sit in class, or talk with your friends. Christ is with you every step of the way, and he wants to encourage and help you. Jesus’ promise is true: “Surely I am with you always, to the very end of the age” (Matthew 28:20).
How can his presence become a reality? First, draw strength from other believers. You mention you made your decision for Christ at a church camp; has that church (or another church) become part of your life? Ask God especially to give you new friends who love Christ and are seeking to live for him.
Then draw strength from God’s Word, the Bible, and from prayer. Through the Bible we listen to what God wants to say to us; through prayer God listens to what we want to say to him. Don’t be intimidated by the Bible’s size, but make it part of your life every day (beginning perhaps with one of the Gospels, such as John).