Hi Christine, Your little Princess is sure to love Bibbidy-Bobbidy-Boutique!
Have you made a breakfast reservation at either Cinderella's Royal Table in the Magic Kingdom or at the Akershus Royal Banquet Hall in Norway in Epcot? If so, you will be sure to meet several of them there. You can also see Alice in Wonderland and Mary Poppins at breakfast at the 1900 Park Fare in the Grand Floridian. If you can't get reservations for any of these, don't worry...you will still have a chance to meet Disney's royalty.
Toontown Hall Of Fame is the place to meet many Disney Princesses and Fairies in
the Magic Kingdom Park. Toontown is located towards the back of the Park near Fantasyland (see your Park Map). There are 2 rooms in the Hall of Fame where your daughter can see such Princesses as Cinderella, Aurora (Sleeping Beauty), Snow White or Belle, as well as Tinkerbell and her Fairy friends. The characters are subject to change, so you'll have to check to see which Princesses are there on the day you visit. Also while in the Magic Kingdom, head to Ariel's Grotto in Fantasyland (see your Park Map). Ariel will be available to meet your Princess there. We've often seen Pocahontas in Disney's Animal Kingdom Park.
There will be a lot of "Meet and Greet" opportunities throughout Disney World. What I would suggest is that you look at the show times guide that you pick up when you enter each park. There will be character greeting times listed on there. If you are looking for particular characters (if you've seen some Princesses at the places listed above and are trying to locate the other ones), stop by Guest Relations at the front of each park and ask the Cast Member for information on where you can find a particular Princess or other character.
Hope this helps and that you and your little girl enjoy every moment of your Magical vacation!
Kaylene