If you want to study to become a CA right after your 12th, you should start with CA Foundation. For being eligible for CA Foundation, you should have completed your 12th in any subjects. There is no minimum aggregate requirement as well. For appearing for CA Foundation, you should have completed your 12th, registered with ICAI and should have completed mandatory 4 months of the study period. There is no minimum percentage requirement. For more information, please visit our page: https://finance.careers360.com/articles/ca-foundation-eligibility-criteria

If you are a commerce student,  you have to have 50% in your class 12 to appear for CA CPT which is required to become a chartered accountant.

For non commerce students, 55% excluding maths and 60% including maths is the cutoff to be eligible.  Also a basic knowledge of computer should be there