第一种
Mathmatics is way too difficult for me. I shouldn't have taken this course.
第二种
I should not have chosen to learn math since it's too hard for me.
第三种
As far as I am concerned, math is too complicated for me and I shouldn't have chosen to learn it.
有问题继续问!
Math is too difficult for me , I shouldn't learn it .
I shouldn't learn the Math for it's too difficult for me .
Math is so difficult for me that I shouldn't learn it .
Maths is difficult for me ,I should not learn it.