Need advice dealing with my mother?

I need advice. I have a bad relationship with my mother, but a decent relationship with my father. I am from NY originally, but have lived in Florida for the last 2 years. My mother's great aunt is turning 100 in February, and there is a big party planned for her. I think I met her all of 4 times my entire life. My mother has been pestering me all weekend that I should go. Deepest apologies, but I am not leaving Florida and going up to NY in the middle of February for a birthday party. Over the years, when I was a kid, this was one of the things I argued about with my mother, her dragging me to family events, since I can't stand most of my family. I know my 16 year old brother Chris is being dragged there. The other day, my mother was on the phone with me, saying "It would be a nice thing to do for your grandmother. It is her older sister who is turning 100. You will be the only member of the family not there. How will that look? There are people coming from California." It kind of feels nice, knowing now that I live in Florida and own a successful business and own my own condo, she can't force me to do anything. I am on the verge of saying, next time she calls. "I am not a kid anymore. If I don't feel like going, I won't. I'm not going, and if you dont like it, you can kiss my ***, and if any of the extended family has a problem, tell them to kiss my *** as well." Can you think of any better ways to deal with this?