First, take a deep breath and relax. You have options.
As I'm writing this, it looks like Florida will get hit by Irma but no one is sure where. Airlines are starting to allow changes without penalty. Norwegian doesn't mention anything on their website, yet, but I'm sure they are following this closely as they fly from numerous airports in the Sunshine state.
Are your dates flexible? If you can't leave early you might in trouble. Check with Norwegian. Even if they can't put you on a plane from Orlando, they also fly out of NY, Boston and Providence, RI. Worse comes to worse, they put you on a flight from there and you will have to take a connecting flight to one of those cities. (No need to fly all the way to the West Coast to avoid the hurricane.)
As stated, you want to be proactive. If you wait, and your flight is canceled, you will be put on the next available flight. That might be the next day. It might not be for a week.
Call the airline and see what they have to say. If you wait until the last minute, everyone else will be calling and you could be on hold forever. 1-800-357-4159