Commerce

yes dear it's a good choice. well done!

See, you can go for BBA if you are interested in management. After BBA, you can only do MBA or sit for exams like UPSC, IBPS, SBI-PO, SBI-Clerk for jobs. If you are interested in banking, go for BCom. After BCom, you have a wide range of opportunities like MCom, MBA, Laws, CA, ICWA, CMA. After BCom, you can sit for the exams I mentioned above. Decide well !!

To stay above average, you must have good grip on all the subjects. If you're chemistry is not good, then you'll be facing trouble in class 11 itself and you'll be frustrated. Your maths is good, so go for commerce with maths. Also keep hindi and econimics. Know this, more successful people are from commerce section than the science. So don't worry about the future. Just keep your marks good in 11th and 12th. All the best kiddo !!

Whatever college you want to go, just check its eligibility.

These are the colleges present for BCA. Just check individually which all take students without maths in +2.
http://entrance-exam.net/bca-colleges-in-kolkata/

Make a list of colleges and just check which all colleges take students without maths.

Yes, for IAS you must take up commerce stream after 10th.

You can go for BBA course because it will teach you business management. You can make use of that later. After BBA, you can go for MBA or PGDM.

If you are interested in banking, go for B.Com. If interested in management, then you can go for BBA.