CBSE 12th

It is not an extremely good profile, as you have scored less marks in class 10th, due to which, the value of your overall profile goes down.

Hi,
You can go for BBA-FIA from DU or can opt BFA, as these both courses will provide you with apt knowledge and skills of finance sector. After that, you can go for your MBA in finance sector.

Hi Swagatam!
The cut-off of St Xavier, Kolkata is generally above 90%. So if you secure above 90%, then only you have the chance to get admission in the B.Com course.

Yes, you can. It is now a one year full time Diploma. The timings are convenient, even if you are pursuing your Bachelor's degree, as per the dual degree scheme of University of Mumbai.

All topics that you have studied in class 12th will be your syllabus of any entrance exams.

Dear Chetan,
You can pursue ACCA. ACCA stands for the Association of Chartered Certified Accountants. It is a leading international accountancy body. The ACCA qualification is recognised and is treated in other countries as being equivalent to their local qualification. For further details kindly visit the below mentioned URL. http://www.accaglobal.com/in/en/about-us.html
I hope this would suffice. All the best and god bless you.

Practice, practice and practice. There is no hard and fast rule, you need to know your weakness and strengths. Practice with previous year papers and improve time management. Make a routine and follow it. Revise regularly. Don't forget to take rest, eat good food and take good sleep besides studying.