Try to respect the fact that your parents are concerned about you and want what's best for you; it's just that in this case you disagree about what's best.
I had a similar problem with my Dad once when I was about 20. He kept wanting me to do something and wouldn't let up until I said: "I know you love me and want what's best for me, and I appreciate that. But I just don't agree on what's best. And it's my decision."
He still wasn't happy, but he quit bugging me!
15 years
