Hi Jaime,
Welcome to the Moms Panel! How exciting to be planning your first Disney vacation.
Of those 3 resorts, I would choose
Saratoga Springs Resort & Spa hands down. Saratoga Springs is an absolutely beautiful Resort. The "High Rock Springs" main pool area is fantastic. We stayed there when our kids were 3, 5, 7, 11 & 15. They all really loved the swimming pools and the walk over to Downtown Disney.
Staying on property you will have access to the Extra-Magic Hours and complimentary onsite transportation which will save you from renting a car or paying a shuttle service.
Disney's
Old Key West Resort is also nice and is located in the same general vicinity. I just prefer Saratoga Springs over Old Key West since it is much newer.
Have a wonderful vacation and please let us know if we can assist you further,
Kaylene