I am in class 12th and want to do integrated course at IIM, Indore. Should I start preparing for CAT now?

One should keep 9 months for CAT preparation, but it is possible to prepare in six months too provided the plan is focussed and exhaustive. For a six month preparation plan, one will need to dedicate 8 to 10 hours daily.

CAT is one of the accepting exams for admission to MBA at ISMR Pune. However, it is not compulsory. Aspirants with a score in CMAT, MAT, XAT, MAH MBA CET, etc. can also get admission. Candidates selected based on their entrance exam scores also need to pass the personal interview round for admission

No, CAT scores are not compulsory for admissions into MBA course at Chhatrapati Shahu Institute of Business Education and Research. The institute accepts other national/ state level management entrance exams too. The names of the accepted entrance examinations are: XAT/ MAT/ ATMA/ MAH MBA CET. 

No, CAT scores are not compulsory for admissions into MBA course at GLA University, Mathura. The university also considers scores from other management entrance exam and one university level entrance exam too. The names of the other accepted entrance exams are: MAT/ XAT/ UPSEE. 

No, CAT scores are not important for enrollment into Masters of Business Administration course at Chitkara University. Because CAT is not the only scores which are considered by the university, it also accepts the scores of MAT/ XAT/ NMAT/ CMAT.