Let me tell you from experience: you shouldn't worry.
I went into the program after my freshman year of college.
True, once in awhile it does happen, that kids drop out and stay at Disney. But it's not very common. Most of the people who stay either a) transfer to UCF, or b) are CPs who just graduated anyways.
My mom had exactly the same worry you did. In fact, she flat out told me I couldn't do it. But she kept making excuses like "You'll be behind" or "You're just doing this to get a vacation." She finally came out with the truth right before I got on a plane to go. In fact, to go, I had to flat out tell her that I was on my own, had my own money to get there, and was going whether she liked it or not. I'm not saying that was the best course of action for me to take, but it got my point across. It's funny, though, because I realized after I said that that she hadn't listened to anything I'd told her. I guess she heard that I'd have to take a semester off and then automatically said no and ignored everything else I said.
So that's one thing I'd say, is definitely listen to her reasons for going, and any concerns/points she has about going. Don't tune them out just because you don't like the idea.
After I got to Disney (and I did go under my own money, for the most part... when my parents realized that I would really go through with it, they woke up a bit ans listened to what i had to say about the program, and even chipped in for nice traning clothes) they really seemed to realize that I knew what I was doing. They even perked up to the idea. And having a family member who works at Disney is a great way to get a cheap family vacation... take a trip to visit your daughter there, and take advantage of the Cast Member discounts! I added up how much I saved my parents when they visited, and it was $300+ dollars cheaper. So that's something to consider!
I did end up staying for a second program, but I think by this time my parents had realized that I was still planning on going back to school. And I did!
As far as living away from home... if your daughter has been living in a dorm at school, than this is a good second step towards having her own place. You're responsible for working enough to pay your own rent, and you have to buy your own food instead of being on a meal plan. But it's not like living in a "real" apartment where you have to pay for utilities, and keep everything up yourself. It's like a middle step between a dorm and an apartment. A nice easy transition.
Career-wise, it helped me see what was out there. It's a great way to meet people, and get to know some of the people in the company and network! In fact, they make that a specific point of the program, and to that end hold a number of networking events with people from all aspects of the resort.
I also found a few interests while I was there that I never considered. I've never acted in a play since being a bit part in the 5th grade school play, but I did a program in entertainment and found that it was something I really loved. Since then, I've been interested in dance and drama. So it opens you up to new experiences! Who knows, she might find something new that she really likes and can continue when she's back at school.
Okay, I've been long-winded enough. But definitely don't say no just because you're afraid she won't finish college. Really listen to her side of it, and look at what else she might get out of it.
-Kirsten