We are called as Christians to be separated from the world. That means that we can not act like the world, or speak like the world speaks. When we are saved and make the decision to live a life for Gods service, it is required that we be different. We have an obligation to reach the lost, and to do this we are called to be IN the world, but not OF the world. We have to live our day to day lives, going to school or work, but we have Jesus working in us and through us and that makes us very different in a very good way. We can give hope to hopeless people, and we can speak strength to people who are discouraged. We have no choice but to live in the world, but the good news is that we don't have to be of the world.
Just remember that being in the world is right where God needs us to be. God wants to use each and everyone of us to bring change to the world around us. We have to make an effort to keep our hearts and minds set on God. 1st John 4:4 says "You are of God, little children, and have overcome them; because greater is He that is in you than he who is in the world." (WEB)
It is not always easy to be different, for children and adults alike, but if we are reading his word, trusting and obeying Him, that makes us very different. Just remember that your unsaved family and friends need you. So dare to be different.