Welcome to the forums, your first question is a big one, but don't worry! "Coming out to your family" is a very big topic, you will find thousands of websites, forums, books, movies, etc. to give you advice. Also there is probably an LGBT organization at your school or in your community with someone you can talk to. Take your time and consider a variety of decisions before you make your decision.
I don't know enough about your situation to give you advice one way or the other. For example are you a minor or an adult, do you live at home or have your own place, is your dad violent/angry/alcoholic, etc.
There are many examples of parents who were against the gay lifestyle at first, but who learned to accept and love their children after coming out. I hope that your father is one of these people, good luck!