Listen to your parents. It is the least you can do after they spent 16 years caring for you, protecting you and loving you. Don't throw all that away over a guy who probably just wants to get some. I'm sure your parents have great reasons for feeling the way they do about it. You will all be happier on the long run if you don't hurt them.
Follow your heart. I'm a Hispanic male who started dating a black woman when I was 15, and my family wasnt happy at first. I stayed with her. I realized many of my family were judging her solely on her skin color not on her character. This made me view many of my family members as racists, and I stopped talking to them. They should want you to be with a person who loves you regardless of that persons skin color. Love is where you find it. You are almost 18, at some point in time they should trust that they raised you well enough to make your own decisions