Hi Karla,
Tinker Bell currently greets guests at the Adventureland Veranda in the Magic Kingdom. She can be seen there along with a few of her Fairy friends. You'll want to be sure to pick up a Times Guide upon arrival for specific character Meet and Greet times/locations on the day you are there.
Unfortunately, Tink does not currently participate in any of the character meals. However, you will want to be sure to watch
Wishes Nighttime Spectacular the evening from a vantage point in front of Cinderella Castle. If possible, stand on the right hand side when looking at the Castle. This is because near the beginning of the show, Tink flies from the top of the Castle, over your heads and into Tomorrowland. It is so magical!
Your little girl definitely can dress like Tinker Bell at the
Bibbidi Bobbidi Boutique! In fact, when I was there a couple weeks ago with my daughter's, I saw several little Tinker Bell's who were getting all pretty and pixie dusted.
Hope this helps and that you have a wonderful vacation with your little girl,
Kaylene