Hi Vicki,
The minimum age for guests to visit the Bibbidi Bobbidi Boutique is three years old, but I can tell you that no one is checking IDs for children.
I do have two other ideas for places at Walt Disney World that your daughter could have some pampering. The
Harmony Barber Shop at the Magic Kingdom will cut little girls' hair and give it a generous sprinkling of pixie dust. You could also go to one of the
salons at the Disney deluxe resorts. Again, your daughter could get a haircut and pixie dust, plus styling and a manicure if you wanted to splurge. You are also welcome to purchase a princess costume for your daughter. These are available throughout Walt Disney World, along with accessories such as shoes, tiaras, and wands.
While these experiences are not exactly the same as the BBB, they can help make your little girl feel like a princess.
Good luck with your planning. Please let us know if you have additional questions.