How do I convince my mother in letting me change classes?

I'm currently in my second year of high school and am taking Honors English II. English has always been my best subject in school but I'm not doing too well this year. This class has become so difficult that many people in my class are thinking about dropping it and switching to the regular English class. One of my friends just switched. I've even thought about switching, considering that I'm not doing as well as I should be. In order to switch classes, your parent(s) have to write a letter to your school counselor stating that they approve of you changing classes. I've talked to my mom about how I wouldn't mind switching classes but she's never given me a straight answer on whether I could or not. I talked to her about it today and she got all pissed off and told me that I'm not putting forth enough effort in this class and made it sound like she didn't want me switching. I then tried to explain that several people are going to be dropping the class and she says she doesn't believe me and even if it was true that I shouldn't be following the crowd. I don't know what to do because I really want to change classes and if I don't change now, I'll have to suffer the rest of the year not understanding anything in this class and getting a bad grade. How could I convince her to let me change classes?

P.S. This is the only advanced class I'm in right now.

Just tell her straight up im going to change classes. If that dont work write a fake note XD j/k.