Hi Laurie!
This sounds like the perfect place to be on an anniversary! I would love to spend my special day with my Prince Charming inside of Cinderella Castle! How romantic!
When you made your reservation, there should have been an option to choose a special occasion for your meal. If you didn't see it, no worries! Just call Disney Dining (407-WDW-DINE), and give them your information (name and reservation number) and they can help you designate the meal as being an anniversary celebration.
If you would like to take it a step further, you can check out the beautiful gift selection offered by
Disney Florist. They have a wide variety of items that can be delivered anywhere on Walt Disney World Resort property, even right to your table!
Also, be sure to stop at any Guest Relations booth to get a free button for your in-laws to wear.
Here is a
great link with different ways to customize your celebration at Walt Disney World Resort.
I hope this helps! Please let me know if you have any other questions.