I took my four year old ( boy ) to see it! There are some sad moments in the movie, and my sweet boy would look at me and say oh, M., this is sooo sad....and we had great opportunities to talk about it later! The movie had a great message, and I think four is a good age. Re: the storms, they didn't register w/ me or my son as scary, but the way I view it is that storms occur all the time, and if your child is scared of storms, you really need to talk to them about them, the more educated they become, the better for them and you! My son went through a "scared" of thunder phase, and we watched the weather channel and borrowed age appropriate books at the library for him to learn about it!! I personally think protecting our children from the everyday things of life ( like death and storms ) make them more and more afraid, and more and more naive!!! Be sensitive, but BE THERE for them!!!
Another opinion, don't waste the extra $$$ on the 3D for a 4 year old! They won't miss it! My 10 year old saw the 3D w/ his gramma, and loved it, but I don't think my 4 year old minded either way! The only movie he loved in 3D was Journey to the Center of the Earth.....
If your still unsure about bringing your daughter, wait til it goes to the cheap show, that way you won't mind so much if you have to leave!
Good Luck!!