Hi Lorna and welcome to the Disney Parks Moms Panel.
In order to ensure that you are able to eat at your restaurant of choice at your desired time, I would definitely recommend that you do make Advance Dining Reservations for all Table-Service dining locations at your earliest possible opportunity.
Advance Dining Reservations can be made up to 180 days in advance online (at 6:00 AM EST) or by calling 0800 16 90 730 (at 7:00 AM EST) from here in the UK.
Cinderella's Royal Table, Be Our Guest Restaurant,
Character Dining and
Fine/Signature Dining locations are especially popular.
I know that it can seem a little bit over the top to book your meals 6 months in advance, but believe me when I say that it will make life a lot easier when you do arrive at the Walt Disney World Resort.
I would recommend that you plan which parks you will be visiting during each day of your stay to begin with and then once you have got your itinerary in place, book your meals accordingly.
Wishing you a magical holiday filled with memories which will last a lifetime!
Emma