Believe me, I know how sad that makes you, but you will still have a wonderful time. I'm 40, and even though my brain knows that those characters aren't real, I still get excited to see them and feel like they are real (at least most of them). I'm so glad we took my DD on her 1st trip at 2 years 10 months because everything was real then and she's a smart one so now at 3 she is already figuring things out which kind of breaks my heart. She has told me more than once on a non WDW character- that's just someone wearing a costume. We were watching Little Mermaid and she said are Ariel and Cinderella real or pretend? Not wanting to lie, but not wanting to tell the truth either, I just said "what do you think? " She smiled and said "They're real" and I said "There you go".
At 2, when we got back from her 1st trip, she questioned where all the princesses towns were like in the movies and where the other castles were. Bless Enchantment. I wasn't above lying and told her I thought it was like Enchantment. There was a door between the two worlds, and the Princesses came out to go to WDW and see the kids for the day, and then went back through and went home at night. She completely bought that one.
You may find that she thinks some are real and others are just people in costumes. :
This is so true!! My DD can spot a fake from a "real"! We had a bad Cinderella at CRT. She didn't look completely right, she was not very friendly, and in our pictures you can clearly see that she is exhausted and tired of the whole thing. We were close to the last family in the lunch seating. In fact, when all the families were through with pictures and she was just standing there waiting to make sure no one else would come in, we were still waiting for a table and my DD asked her a question ("Where's Prince charming today?), and she completely ignored her and turned away from her, even though we could tell she heard her. My 3 year old DD quickly determined that she was not the real Cinderella, but just someone in costume pretending because the "real" Cinderella was over in Toontown. (Luckily, the upstairs princesses were all great, but my DD still says she would rather go back to Akershus where she went when she was 2 - at least until I remind her of the ice cream with the chocolate crown on top at CRT)
DD was also skeptical of Ariel at her Grotto, even though she was a great Ariel and she still loved her. We got--- I'm not sure that's Ariel. If we are not near the ocean why does Ariel have her tail? (maybe because she knows kids want to see it) She's married to Prince Eric now, why does she have her tail again? (remember Little Mermaid II- her Dad let her have her tail again to swim- he probably does that here). How could he get here to do that if there is no ocean? (maybe he did something at the ocean with his trident so that she can make her tail come and go whenever she wants). Can we ride Peter Pan again? (Whew).