IIMs shortlist candidates for the interview stage based on their own criteria, which may be independent of each other. The process may include Written Ability Test, Group Discussion, and Personal Interviews. Performance in the CAT examination is an important component in the admission process. IIMs may additionally use other factors such as the previous academic performance of the candidates, relevant work experience, gender and academic diversity and other similar inputs in shortlisting and ranking of candidates at various stages of the admission process. The processes, academic cut-offs and the weights allocated to the evaluation parameters may vary across IIMs. You have a very good Academic profile barring your 12th. So if you can manage a score of 95 percentile and more, you can secure a seat in an IIM.