Welcome!
As most people have mentioned above, you have plenty time for planning for your holiday. I found these boards shortly after we booked our holiday this past January and I've been on them most days since
I've picked up LOADS of tips and ideas what I'd never heard of before, which will hopefully help us out when we arrive. I'd advise that if you find a thread on these boards that you wish to 'monitor' (so you can keep coming back to see any further up-dates), then subscribe to the thread, because they easily go missing in a single day, that's how busy these boards get!
Getting back to your holiday, it all depends how long you're going for, where you're all staying and what your individual family is into. If you all enjoy the thrills of rollercoasters, then make sure to include a couple of days down at Universal, on the other hand, if you're all animal lovers, then make sure to add SeaWorld to you're trip also. (Don't forget also, by the time you arrive, SeaWorld will also have it's new waterpark, Aquatica open, so you may wish to check this out for half a day too!)
Your children are at a good age to enjoy everything, they'll be tall enough to ride, and yet still young enough to enjoy the 'magic' of the characters etc. I'd make sure you watch out for you're 180 day to go mark (I know it's a long way off yet, but it'll soon arrive!) because you'll then have the chance to try to make reservations in some of WDW's restaurants, including character breakfasts and lunches. You'll pick more information up about this as you read different threads on what is on offer and you can then work out what will suit you're tastes.
Hope that helps for now, by all means send a PM to me if you need any further information on the lead up to your trip, and if I can help in anyway then I will!
Welcome to the DIS...enjoy!