YOU SAID:

I am going into marching band this year

INTO JAPANESE

私は今年マーチングバンドに入る予定です

BACK INTO ENGLISH

I will be in the marching band this year

INTO JAPANESE

私は今年マーチングバンドに参加します

BACK INTO ENGLISH

I will join the marching band this year

INTO JAPANESE

私は今年マーチングバンドに参加します

BACK INTO ENGLISH

I will join the marching band this year