Take it, without question. Even though I had a professional internship with Disney in their design department, it was the best job I've ever had. I know many people who have worked or still work for them in their parks and they also love it. You're working with a ton of people your age, networking, making lifelong friends, having a blast and working on shows and productions that many people dream of doing. From your post, you get to do some traveling on the company too! It's an experience you just can't replicate anywhere else. And, at 19, if you hate it for some odd reason, you can always do something else.
Just as a tip, learn that the resort in Florida is the only Disney World, the rest are all Disneylands. From what I hear, Tokyo Disneyland and DisneySea is crazy awesome! So, if you have a chance to travel to the different parks, DO IT!!!!