Stephanie,
An amazing amount of work completed in an hour! It's plain to see you will do just fine with faces. No need for trepidation 
You just need your confidence in place. A face is no different than drawing anything else. Shape, size, value, edge. It just has more in it to pay attention to, so a face takes a bit more time than a different subject would of the same area/size. Also mismeasurment or misplacement is easier for the average person to spot in a face.
Still, the same skills that allow you to draw a horse, cowboy boot, or your daughters figure, will serve you every bit as well tackling this face, so long as you give it it's extra time in careful observation.
It's obvious from your start, that you are easily well within your considerable ability with this drawing. Go forth boldly, but patiently. 
Carl
I have been dreading any attempt on a face and I thought doing a profile would be easy but first off my drawing will be the profile of a man with the full side of his mule. His actual face from the top of his hat to his chin is only about 1" and I am finding it very difficult to get the tiney details. I had my daughter critique it because she knows the man and her only comment was "Mom, it's amazing but he looks 10 years younger. You need to add more wrinkles under his eyes". 
I told her that I'm sure he would appreciate that. One thing I have found doing my commissions is that people always <perceive or want> their animals prettier than they actually are. 
