My dad can be the very same way sometimes. I agree with sweetpea03...but i think you should also consider his views to get a better understanding of where his ideas are coming from.. this could help you convince him otherwise. Maybe he is sad that he is losing his child, many parents go through that. Maybe he is trying to give you all the things he wanted when he was a child, but couldn't have. Things like that. Good luck.
I'd do some research and show him otherwise. Sit down and show him that if you go to a public high school, you can stay in honors classes and keep your grades up. Show him the statistics on the public high school and talk about needing the best way to get into college, by making connections and networking. Being able to have a counselor to talk to about what classes are best and helpful hints about doing your best in school. You can say that you are getting older and want to take on more responsibility by getting a part-time job, so that you can save up money for your future. I'm sure your father wants the best for you and means well, so show him that this is the best thing for you to do. Hope it goes well.