Nothing is impossible. Be who you want to be; not who someone else wants you to be. If you want to be a Movie star, Doctor, Singer/Pop star, Chef , Professional sports star... be it. If you want to be a Teacher, Writer, Comedian, you can. Believe in yourself and others will start believing in you too.
Stay positive and if you feel like you are coming in contact with negative people go the other way. Family will always be there for you; whether it's your real family or best friends. If you have people in your life that are there for you during the good and bad they will continue to be. Remember to stay positive!