Hi Mia! Sounds like you are planning a fantastic first trip to Walt Disney World!
My first choice would be Disney's flagship resort, the
Grand Floridian. It has large, luxurious rooms, a fun pool, great restaurants, and a fabulous location on the monorail route right next to the Magic Kingdom park. If the theming of the Grand Floridian doesn't appeal to your family, take a look at the
Polynesian or
Contemporary resorts. Both are also on the monorail route, which makes traveling to and from the Magic Kingdom super easy.
My other recommendation would be the
Beach Club. It also has large, luxurious rooms, and a spectacular pool area with a huge water slide that your children would love! Although it's not on the monorail, it has boat transportation to Hollywood Studios, and Epcot is a quick walk or boat ride away, giving you lots of dining options.
If money's no object, consider staying in a club-level room at one of these resorts. You'll receive assistance with dining reservations and other vacation plans before your trip, and access to a lounge with continental breakfast, snacks and drinks throughout the day, and evening wine, beer, appetizers, desserts and cordials. The ability to grab a drink from the lounge on your way out to the parks or unwind with a glass of wine in the evening while your kids have a pb&j sandwich makes for a really relaxing time!
Have a wonderful first visit to Disney!