Hey, I have taken graduation after 10th and i'm currently appearing for my third year of graduation in BCom. I have not done my 12th exams.
10th and 12th standard marks do count for admission into IIMs and not for the CAT exam!
CAT percentile is only the starting point of the admission procedure. Each IIM has their admission criterion.
For furthermore information please go through the link given below :
https://bschool.careers360.com/articles/cat-eligibility-criteria
For SNAP eligibility please visit the link given below :
https://bschool.careers360.com/articles/snap-eligibility-criteria
I hope this would help you. For further queries please feel free to write me down in the comment box.