E.W.
N.,
My 2 1/2 yr old son loves cars, and got super excited
watching the commercials for the movie Cars. We have never taken him to a movie (except when he was little enough to sleep through our picks) and we decided that this would be the right first movie. It wasn't. We had to get there a bit early to get good seats. The previews were 20 min long and he was bord already. My fiance and I had to take turns leaving the theater with him off and on when he didn't want to be in there. And every few min my son kept saying "I want to go home"
We watched about 3/4 of the movie when we left.
If you do take your daughter get there when the previews are almost over, so she can start enjoying the movie when you sit down.