Hi Michelle,
Do a search on the theme parks and attractions board and you will find lots of threads on LMA.
The show is 35 minutes long and you'll need to allow at least 5-10 minutes to get out of the stadium after it ends. There are only three shows per day, usually around 1, 3:30, and 6 (give or take half an hour).
It can be loud, with lots of tires screeching and motors revving, but only you would know if it would bother your daughter. Some babies are super-sensitive to noise, others are not.
As to whether you will enjoy the show, I too suggest you ignore the opinions of others (including mine, because like Sandi above I didn't really like it either, but unlike Sandi, I'm a male!) and try it yourself!
Bob