Of course you should not have to dissect anything you do not feel comfortable with. I will tell you that in the early 80's when I was in high school, people were dissecting fish and frogs, and I refused to do it. No negative recourse happened to me at all.
I am also a teacher and would never, ever 'make' my students do something they are not comfortable with. You don't need to dissect to learn.
Lori Cumiskey, B.A., B.ed.