Hi Angela:
You should find plenty to keep you and your family entertained during your first evening of your visit. I'm not sure if you are staying on property, but you may want to explore your Resort's pool that first day, or hop on the monorail to check out the Contemporary, Polynesian, and Grand Floridian Resorts where you can window shop or dine at a restaurant (the dining part isn't free). A number of Resorts feature a
movie under the stars at night, weather permitting. There are also a ton of fun shops, restaurants and activities at
Downtown Disney. There is no admission fee for Downtown Disney so you can stroll around, but a great experience that comes with a fee, is
Characters in Flight, which soars 400 feet in the air and offers breathtaking views of Walt Disney World property and beyond. You can also check out
Disney's Boardwalk area which features some very entertaining street performers in the evening.
Enjoy your vacation.