Her name is McKenzie and she has a few other video's out there. The most popular one is where she's at a pistol defense class. Her gun isn't jamming in the video due to poor maintenance or a defective weapon. Her father admited to loading her pistol with snap caps (dud trainers) to make her have to perform "slap and rack" drills. From the videos it also looks like he added a few half full magazines to make her run reload drills as well.
http://www.youtube.com/watch?v=bDlodGEp_9o
With the added drills it looks like she was training harder than the grown ups.