Well, for the first few weeks of the semester, you can switch, using a form at the registrar's office. And they're all the same cost, so it's really easy.
19 meals a week means that you have three meals a day during the week, and two a day during the weekend. Now, that's great, if you like getting up extra early for breakfast. Look at your first class. Look at whatever time you'd have to wake up to get there on time. Compare that with 20-30 minutes less of sleep. If that's for you, then great! If not, consider going to the 14 or 10 meal plan. Also, on the weekends, Drew has less workers, so the quality and variety of food goes down. For some, this is a bigger deal than others.
If you're on the 14 or 10 meal plan, you get points on your card that can be used at the snack bar, or to get in to the commons, if you want to go to the commons more times than is on your plan. If you're on the 19 meal plan, you can spend a meal at the snack bar and get a certain amount of money there (I think it's like $4.50 or something, very little for supper).
but, since you can change, you can try it for a week or so, then switch, and then still have time to switch back before they don't let you change any more.