Hi Marsha!
So, first trip for the little princess? How exciting! I can remember taking my daughter for the first time (age 3). I was excited (which isn't much for me when we're talking about Disney), but so much more excited for her!
Here are a few "must do's" for your daughter:
Magic Kingdom
Cinderella's Royal Table at Cinderella's Castle-yes, it can be a little pricey, but serves as one of the best places to get up and close pictures with Cinderella. Some others you should expect to see are Snow white, Jasmine, and Belle. My daughter was star struck there :-)
Peter Pan's Flight/Magic Carpets of Aladdin-two toddler friendly rides that are very fun.
Epcot
Kidcot Fun Stops at World Showcase-my children loved these stations, which have fun and engaging crafts for little one's.
Akershus Royal Banquet Hall (Norway)-another place to see many of the Princesses, such as Cinderella, Belle, Ariel, etc.
Hollywood Studios
Playhouse Disney-Live on Stage-see acts such as Little Einsteins. Handy Manny, Mickey Mouse Clubhouse, etc.
Playhouse Disney at Hollywood and Vine-sit for breakfast and enjoy singing, dancing, and good eating with Playhouse Disney characters.
Voyage of the Little Mermaid-a short show starring Princess Ariel
Animal Kingdom
Affection Section-area where your daughter can pet the animals
Kilimanjaro Safari-one of the best attractions at the 4 parks, in my opinion.
The Boneyard-my children could have stayed here all day. Your daughter can be a little paleontologist.
So, these would be my "must do's" at the parks for family and daughter. Have a great time!