kyou ni watashi gaku ni ikimashita (kee-oh ni wa-tah-shee gah-ku ni ee-kee-ma-shtah) literally 'today I school to went'
Although you should specify what kind of school.
High school: kougaku (koh-gaku, elongate the 'o' in shou)
Primary school: shougaku (shoh-gaku, elongate the 'o' in shou)
See the related link for Google's translation.
ikimashita
学校にいた is how you say I was at school in Japanese.
Today is 'kiyou' in Japanese. im hindi it is aaj
kazan ni ikimashita
gakko no kamoku
Kyou, doko ni imasuka?
It is grammatically correct to say , "I am in school today." This is because you are in the building, not at the building.
Nyūsatsu no gakkō
Kurai kage gakkō
kyou no jigyo WA nandesuka
Kyō wa totemo kodokudesu