Yes, getting 90% in 12th is a good score, and it can help you get into an IIM, but it is not the only thing needed. To get into IIMs, you must also do well in the CAT exam, which tests your aptitude in English, Maths, and Logic. Along with CAT, your 10th, 12th, graduation marks, work experience, and interview performance also matter. Each IIM has its own selection process. So, focus on preparing well for CAT and build a strong profile. With the right effort and strategy, getting into an IIM is definitely possible.