My DD's and I started to travel to Disney with my father when they were a bit younger than your DD - now we are hooked and visit every year together!
The first trip was very magical (actually they have all been magical), but I wish I had done some planning on our first trip. The fact that you have ADR's booked and are searching here on the DIS puts you ahead of most first time visitors. The best advice I have been given here is to enjoy the moment, make memories and don't try to accomplish everything on one trip! The fact that you'll likely catch 'Disney Fever' just makes it fun to plan a return trip to do things you didn't get done on the first trip. Regardless, I think your DD is the perfect age to go to Disney and will love everything you have planned.
Suggestions for each park:
MK- BBB reservation (if your DD is into princesses) or Pirates League reservation (less $ than BBB and a lot of fun), Dole Whip for you and your mom
Epcot- Soarin', Kidcot stops at each country. You and your mother may enjoy the cultural aspects of each 'country' and enjoy a treat / beverage while DD gets to do a craft.
Animal Kingdom- Boneyard, Safari,
DHS- TSM, Animation Academy, cupcake from Starring Rolls
I would also recommend to be sure to do the shows as well as the rides. They are enjoyable, relaxing and part of the magic (FOTLK at AK, Laugh Floor, COP and Philarmagic at MK, BATB at DHS, World Showcase and Turtle Talk at Epcot).
Resort- assuming that you are staying at a Disney resort, enjoy the pool!
Downtown Disney- shopping and making your own treats at Goofy's Candy company. We like Hanes 'Build Your Own Tee" at DTD and make a shirt for each trip.
Boardwalk- evening stroll (maybe after Epcot) and ice cream from Beaches and Cream.
Wishing you a magical trip