Since you said you've paid a $200 deposit, I'm assuming you booked a package. In order to apply the AAA discount to a package, you must book through an AAA
travel agent. You'd have to cancel the package you have booked now, and re-book through AAA.
If you booked a package w/ just room and tickets (no dining plan), you could cancel it and re-book through your existing agent as a room-only reservation and then purchase the tickets separately - through the agent, online or through Disney. Room-only reservations w/ AAA discount can be booked through AAA, Disney or a regular travel agent. Personally, I'd recommend the package because you can add the Dining Plan (a great savings over paying OOP for food) and you get the parking pass and Diamond Card for savings in Downtown Disney. Also, if you book an AAA package in January you get a $25 Disney gift card!
I think the AAA discount and perks are awesome! The most important factor in booking through AAA is using an agent who knows Disney. He/She doesn't have to be in your state, you can have your docs shipped at no charge, so definitely shop around and find someone you're comfortable with. I live in Colorado and use Stephanie at AA Mid-Atlantic (who's also a DIS member!). She's incredible - always quick to respond, on the phone with Disney to apply codes before I'm even out of bed, and she doesn't mind that I'm always wanting to make changes.
