Hi Kerri!
Although a credit card is required for some online booking, if you purchased a dining plan with table service, you can still use your dining plan credits when you get to the restaurant.
The credit card allows Disney to secure the reservation, as well as have a source of payment if a reservation is missed (a fee is charged for missed reservations, or reservations cancelled less than 48 hours prior).
What will normally happen is you book your reservation online now and get a confirmation number. If you got a vacation package with Standard or Deluxe Dining, when you get to the resort, they will give you your resort key card (called the Key to the World card). You can use that card not only to get into your room, but also to pay for your meal with your Dining Plan. The key card can also be used to get into the Theme Parks.
For more information on the dining plan options, click
here.
Not too much longer before your time at the "Funnest Place on Earth" begins. Good luck and wishes for a magical time!