Hi there Georgia! Thanks for visiting us here at the Moms Panel. We are so happy to assist you with your planning. It's so exciting to plan any trip to the Walt Disney World Resort, but your first trip? Wow! I can assure you that you will want to keep coming back. There truly is something for everyone! All of the restaurants will try as best they can to keep you together. However, they will not be able to guarantee that you will all be seated together. When I travel with a large group, I notify the folks at (407) WDW-DINE that we would like it notated that we are dining together. When you check in for your reservation, let the host or hostess know that you would like to be seated close together, if possible. It is recommended that you arrive at the restaurant 5 minutes prior to your seating time. When traveling with a larger group, I recommend arriving 10-15 minutes in advance of your reservation.
I also want to direct you to some really useful information for traveling to Walt Disney World with a large party. Take a look...
http://disneyworld.disney.go.com/planning-guides/in-depth-advice/large-party-planning/ Here you will find some valuable information regarding accommodations, if you should need it.
You will be surprised how enjoyable it is to roam the parks together. However, if you are looking for specific tours, try calling (407) WDW-TOUR for suggestions.
I wish you a magical vacation!
-Jacqui