Hmmm...that depends...you could do either and get caught and suspended (at the least...maybe expelled). Is it really worth it? This is the perfect life learning experience. You might as well get used to working with a difficult teacher now because you'll be forced to work with difficult employers as an adult. Suck it up and find ways to do your best and deal with her. That way, you know that, no matter what, you tried your best.
Talk to her outside of class and explain that you are new to sculpting, and that the more she nags you, the harder time you have. If that doesn't help, and she continues to get to you, go to a "higher up" in the school. If you're in high school or younger, go to the principal...college go to the assistant dean or dean of the art department. Don't get into a bickering contest...just state your case calmly. Maybe he/she can get things straightened out.