This is going to sound a little harsh, but you have to grow up sometime! It is a fact that your parents are not going to like everything that you do. Sometimes you will know what is really best for you and they won't! In this case you are going to have to say, "Dad, I respect your opinion, but I am going to prove you wrong." And then do it! Also, think about where he went to college and what the Greeks were like there. A lot of people think "the greeks where I went to school 30 years ago were wild and crazy, so they must be now" and that just isn't (usually) true.
As for parent's... well, frankly, my parents never gave a rat about what I did or anything like that, so I can't really relate to the feeling of parents interfering with stuff like that. But I hope everything works out!
Allie