You've been lied to by the Weather Channel and other fear-mongerers. Even the initial tracking shown it blowing out to the North Atlantic. Who decided that it was going to go up the gut of FL, like some horror movie?
The European model has been more accurate all along. It has been predicting North-West direction all along. What makes the hurricane change direction on water is low & high pressure regions it encounters. But you are correct in that every moving body has momentum, and it will want to keep moving in the same direction it is moving. This storm is so huge in diameter, which means it also has a huge momentum and inertia.
You are wrong.
That said, hurricanes can, and do, make sharp direction changes. Here is a link to Hurricane Betsy, which made a loop and then a near 90 degree turn in 1965 just so she could pass over my (not the same, but nearby) house....
Lots of other storms have done crazy turns: StormHistory
O2