That's a great time of year to visit Walt Disney World. The weather should be a little cooler compared to the summer and the crowds will definitely be less. Be sure to order the free Walt Disney World
planning DVD.
I also recommend picking up the book "The Complete Walt Disney World"
by Julie and Mike Neal. There are a lot of good tour books out there,
but I especially like this for first timers as it is packed with photos
and some good tips; the photos help to get everybody excited for the
trip and give a glimpse of all of the wonderful things to do inside and
outside of the theme parks.
With a 3 year old daughter, you will probably be spending a lot of time in the Magic Kingdom, the crown jewel of the Walt Disney World Resort. Thus if your budget allows, I recommend staying in a Magic Kingdom resort on the monorail. All three are nice, but I like the Polynesian Resort the best. It's very romantic as well. If you want to stay at a resort within walking distance, then make a reservation at the Contemporary!
In my opinion, one of the biggest mistakes a first timer sometimes makes
is not making dining reservations. Advanced Dining Reservations (ADRs)
can be made up to 180 days in advance. I think the ADRs are critical
if you want to dine in a Table Service (full service) restaurant. While
not all reservations need to be made 180 days in advance, you should
know that some of the most popular restaurants will in fact book up
quickly. You made make on-line reservations
here.
This should get you started. Write back with some more detailed questions when you are ready!