B.Com

You can specialise in Cost and Works accounting or banking and finance both will help you if you decide to go for master level programs like MBA or PHD

Few universities such as Delhi University allow stream change at graduation stage. Therefore you are eligible to do Commerce graduation even after Maths & CS stream at +2 stage. But every university have a criteria of disadvantage for such stream change. In DU colleges 2 to 4 % marks are deducted from best of 4 subject marks. Therefore your cut off will be 2 to 4 % higher in comparison to candidates who had Commerce at +2 stage. You can become CA with out graduation also.

its depend your interest you should do Masters in commerce or MBA.

Hey Surbhi,
It doesn't matter how many marks you got in your exams. You just need to focus on what you can do better. If you feel like you can do Eco Hons you should go for it. Marks can't define your career. You can go for Eco Hons that will be better for you. Also along with the course selection you need to select a good college to pursue your degree which can give your career a kick start. Some university suggestions -

99.9% for all exams to get into iim