I have Extremely poor 12th scores. Do I even have a chance at good IIM's

So here is my profile.
I’m an engineering student in the 3rd CSE branch. I’m from a tier 2 college. There are good opportunities but I am not very sure if I’m interested in coding anymore.

My profile is 10CGPA in 10th, 69% in 12th and My CGPA right now is ~9.6
I have neither started preparing for CAT nor I know about its difficulty level. I came to know that OLD IIM’s like ABC and L take school marks into consideration.
Adding to the damage is that C and L have higher weightage to 12th marks and C doesn’t even consider grad marks so that I could compensate for my 12th marks.

Fortunately I clear the 80% 10+12th average cutoff for IIM A, but B seems to be a no chance since I heard that they don’t call people with poor acads.

Im new to this forum. I don’t really know how to go forth with preparation. Any sort of guidance would be highly appreciated.