failure is always an option

http://www.odemagazine.com/doc/57/in-praise-of-failure/all

...particularly with drawing.

Let's look at how you define failure with drawing.

Have you failed if you do not draw what you have conceived in your head before you began the drawing?
In this class, you should be drawing what you see, NOT an ideal figure.

Have you failed if you do not draw what you see in front of you?
How much do you really see? Are you focused on details or the overall picture; the overall figure? What is more important; the individual fingers and small facial details or torso, legs, arms, head?

Have you failed if you make mistakes?
If you don't make mistakes, then how are you going to learn anything other than what you already know?