Law

Here is one exhaustive list of taxation diploma course in India and The colleges which offer the same.
https://banking.shiksha.com/diploma-in-accounting-taxation-courses-in-gujarat-categorypage-4-74-528-0-0-1-109-2-0-none-1-0

You have good prospects into Legal department of huge companies where Tax and Compliance and Audit issues are pertaining. All of these shall be covered in BBA And LLB, So a good career choice.

Amity law school Delhi is better option according to my view . but choice is yours.

yes you can do it , which can entice more job opportunities in future you need to prepare for clat exams and CS foundation too.

If you have got any compart . you need to pass your plus 2 exams without any cross in any subject. so I think that you should not take admission in any college yet. Firstly gear yourself to study twelve class basics thoroughly and after one year fill the form of college of law and exam of law such as clat, lsat , ailet, dullb to prepare for law you can get enrolled yourself in best coaching near your home and try to study as more as you can . Best of luck .