Hi there, Sheila!
I actually spent a little bit of time hanging out in the absolutely gorgeous lobby of Disney's Grand Floridian Resort & Spa a couple of weeks ago while
My Disney Girl's Perfectly Princess Tea Party was going on. What a special treat it was to look in on!
If I had to give my best guess, I'd say that most of the children there were between 5 and 10 years of age. They were all dressed up in their own Princess gowns and it was a very fancy affair! I loved listening to the faint giggles; it was very sweet.
As far as your daughter being too old, I'd say that it really depends on her personality. She's certainly within the age bracket of children that are able to attend this very special experience. Of course, I can't say what ages of children will be attending on the day you take your daughter, but you could talk to her about that and see how she feels about it. One adult must attend with her, so it could be a fun Dad/Daughter or Mom/Daughter experience and she won't be alone.
I sure hope this helps with your decision, Sheila! Please feel free to write back in if we can help with any other questions you have.
Wishing you and your family a Pixie Dusted vacation!
~Jackie