Maths Eligibility

Yes, you are eligible for BCA course of Devi Ahilya Vishwavidyalaya, Indore. The eligibility criteria and other details are given below.
ELIGIBILITY: Higher Secondary (10+2) with 50% marks and Mathematics as a subject.
AGE LIMIT: As per the directives of Government of Madhya Pradesh, there is no upper age limit for admission to various programmes.
ADMISSION PROCEDURE: The admissions will be done as per merit in the entrance test conducted by the university.
SEATS: 90 (reservation as per state Govt. rules).

Yes, you are eligible depends upon the university cut off that whether you will get that university or college or not.

The eligibility criteria of B.Sc. Computer Science of SGGS College Chandigarh is given below.
Eligibility criteria : A student who has passed with minimum of 40% marks in aggregate in respective Science group (PCM/ PCB) in +2 examination of a recognized Board.
So Arts students with Mathematics are not eligible for this course.

As per the UPSC's eligibility criteria of CDS for OTA (Men), the candidates need to be unmarried and should have age between 19-25 years. Every candidate who is willing to apply for CDS 2020, must have completed their Graduation or at least is appearing for the final exam of the degree. So you can not apply right now and wait for next year.

It will be good if you go for BBA or B.Com, because you have done commerce and said degrees give you an advantage when you shall join MBA in finance in the future. Now in all degree programmer computer learning is essential. Thanks and Good Luck