I would say that a meal at Cinderella Castle should be plenty to make her feel special! Be sure to note the birthday celebration on your reservation. When we had dinner there (May 2014) for my daughter's 6th birthday, I noted it on the ADR. When we arrived, a special Happy Birthday placemat (signed by all the Princesses) was waiting at her place, and later, our server brought out a birthday cupcake with a lit candle to mark the occasion. These things were done without my asking for them, and in addition to the usual fanfare (kids given magic "wands" or swords, princesses circulating to greet them). My daughter was totally delighted at how specially she'd been treated, and was walking on air for the rest of the day.
We also let her wear her Princess Aurora gown (brought from home), which made her feel right at home in the Castle. (I had a back-up outfit in my purse, which she changed into afterwards, as she preferred not to tour the park on a very hot day in a glitter-and-polyester dress!)
Have fun!
P.S. I would have your wedding anniversary marked on any ADRs you have for the anniversary date, as well. It's not guaranteed, but sometimes servers will bring out a special dessert or other treat to wish you well.