YOU SAID:

School is so hard that I don’t have good grades.

INTO JAPANESE

学校はとても大変なので、成績が良くありません。

BACK INTO ENGLISH

School is so hard that my grades are not good.

INTO JAPANESE

学校はとても大変なので、私の成績は良くありません。

BACK INTO ENGLISH

School is so hard that my grades are not good.