CA

No problem what you had in XII.
While pursuing CA course, everything is taught starting from the basics of accountancy, economics and maths. No worry.
But remember you need to be dedicated and focused on what you are doing. Because lack of attention while doing this course could spoil precious years of your career.
All the best!

Hi,
CA per say has no specific requirements of any subjects till 12th, so students from any stream can apply but commerce helps you in the basics and is an advantage. For all information you may check. Their website is www.icai.org

You can also pursue accounting technician course.

It is a good idea to pursue CA after completing BAF. The minimum package depends on individual's ability and the organization. Generally, the salary for CA is around Rs.15 LPA to Rs.16 LPA and the minimum expected salary is Rs.9 LPA.

You should not try CA, if you don't like accountancy. This course needs specialization in accountancy. You must try CS, if you are interested.

No, it won't be tough as the syllabus correlates.

B.Sc in economics will be a good option for you.

It's better to do a graduation degree course before CA because that can come handy for you in future.