Company Secretary

Hi you can pursue CS along side B.Com. If you're sure that you can manage both at the same time then you should definitely take it up but do continue your B.Com as well. The career options are good when you combine both B.Com and CS. Stages to become a Company Secretary:
The student who would like to join the Course after 10+2 pass or equivalent has to undergo three stages to pursue the Company Secretaries Course I. e. Foundation Programme
Executive Programme
Professional Programme
The Student who would like to join the Course after passing the Graduation has to undergo two stages of the Company Secretaryship I. e. Executive Programme
Professional Programme
Foundation Programme can be pursued by 10+2 pass or equivalent students of Arts, Science or Commerce stream (Excluding Fine Arts)
Executive Programme can be pursued by a Graduate of all streams except Fine Arts. Professional Programme can be pursued only after clearing the Executive Programme of CS Course.

As per your past academic record, your probable standing are as follows:
1. For class 10th, your score is 2 out of 10
2. For class 12th, your score is 2 out of 10
3. For Bachelor's degree (if Science) your score is 10 out of 10
So, Application rating (AR)= 2+2+10=14 out of 30
The shortlisting of candidates or call from IIMA for AWT and PI will be done on the basis of your composite score= 0.3 (Normalised AR score) + 0.7 (Normalised overall score in CAT-2018). The upper limit of candidates those will be shortlisted in your category is 57. The Normalized AR score of an applicant is equal to their AR score divided by average of the top 50 AR scores from the applicant's pool, (the applicants pool in this case being defined as the group of candidates who appear for CAT-2018 and apply to IIMA.)
So, in my opinion your composite score is quite good because of performance in graduation and CAT Hence you have a good chance of IIMA call. Good Luck.