Welcome aboard, Ryan!
Your little princess sounds a lot like my daughter at that age, and still now as a teen! She adores being pampered with a manicure or pedicure, so when she can indulge in this treat at sea with Disney Cruise Line, it's even more special!
Senses Spa is for ages 18 and up, and
Chill Spa is for teens. However, for certain treatments, like my daughter's favorite Me! Bath Ice Cream Manicure or Pedicure, the Cast Members in the Spa have been happy to treat a younger girl with a parent along, so we've done this a few times when my daughter was much younger, and she continues to enjoy it now. My daughter loves the Me! Bath Manicures and Pedicures because she gets to choose a scented "flavor", (usually her pick is chocolate), and then enjoys a soft serve ice cream after her treatment. The manicurists have also offered to add a tiny little hidden (or not so hidden) Mickey on her nail, which is so cute, and perfect while sailing with Captain Mickey and his crew.
You won't be able to pre-book this experience for your daughter, since the treatments can only be pre-booked for those within the age range of the spa, but once you're onboard, head up to the spa and chat with the folks there to set up a time. Hopefully they'll be able to include your daughter in this fun experience while you're sailing.
Enjoy planning, Ryan, and please swing by again if you have any other questions about planning your cruise. We're happy to help!
Marcy