we just took my DS in January, at the age of 19 months, and he ***
LOVED *** it!!! We thought that he would enjoy himself, just because it's a fun place, but he got ALL into everything that was going on. After being a tad tentative on his first character interaction, until Dale sat down on the floor with him and patiently coaxed him to play - after that, he LOVED playing with the characters. He liked a lot of the rides but I think he just had a blast BEING there - like the fountain in epcot where the water comes out of the sidewalk - I didn't know he could laugh so hard - he would have spent all day there if we'd let him!
He didn't know Mickey Mouse before we went, because he doesn't have any Mickey Mouse cartoons, but he sure knows him now! He did get extremely excited when he saw the characters he knew - like Buzz and Woody, and Mulan. But the biggest thing for him was getting to see Bear in the Big Blue House live at MGM - you would have thought he was in the presence of royalty.
When he saw Bear from up on my shoulders at the Stars and Motor Cars parade, he waved so hard and shrieked so loudly with joy that all 5 rows of people lined up in front of us all turned around, smiling, and watched him instead of the parade for a few minutes.
I would say *definitely* take her. If you guys liked to go already when you were single, and she's so young now, you should maybe consider looking into the Disney Vacation Club when you're down there. It's what is making it affordable for us to be able to take DS back many times while he is still very young.