I know the feeling of being talked down to by a teacher. I loved drawing anime/manga, so I enrolled in an art class. My teacher kept giving me crap about my art and it seemed like she didn't exactly like anime/manga (she didn't say it directly, but I knew). When I drew a self-portrait of myself in manga form, she said she liked everything about it except the face. I believe it was because she didn't like manga. When I drew a still life of my watch I use to wear, she accepted it with open arms. This goes to show how a hypocrite she was.
I would follow
>>4's advice. If you teacher thinks you are making mistakes, then you should constantly ask her questions on assignments that she gives you. She IS a "teacher" after all.