Forgive me if this popped up recently, but I don't think it has. Cineplex.com is listing the running time of Equestria Girls at 1 hour and 12 minutes, meaning it's a bit shorter than your usual kids movie.
They also have a somewhat updated synopsis, different from the last post:
When a crown is stolen from the Crystal Empire, Twilight Sparkle pursues the thief into an alternate world where she transforms into a teenage girl who must survive her biggest challenge yet… high school. With help from her new friends who remind her of Ponyville’s Applejack, Rarity, Rainbow Dash, Pinkie Pie, and Fluttershy, she embarks upon a quest to find the crown and change the destiny of these two parallel worlds.Hope you all are in the mood for some principal Celestia and lunch lady Granny Smith!
Thanks to Firestorm for the heads up!