CBSE 12th

Firstly, please don't worry. As your marks are not the only parameter to judge yourself. As per your marks, I think you need to re-strategise your career plans. If you are not interested in maths or did not have enough command in maths, so I suggest to move in that field in which you have both the command and interest as well.
Best of luck.

You should be qualified in 12th standard or equivalent examination Science stream with physics, Chemistry and Mathematics as a main subject. You should score minimum 80% percentage of marks in 12th standard. You should qualified in AIEEE BITSAT JEE Entrance examination with good percentage of marks.

Hi shibil,
For being eligible to write TANCET examination, you should be graduate with atleast 50% in any discipline final year graduates are also eligible. Hope it helps.
All the best for your future.

Yes, of course. You can see many people who have opted for CA after MPC. Just move on.

For pursuing B.Sc in CS/IT you need science stream in your 12th without it you are not eligible for B.Sc because B.Sc CS includes maths, computer and physics as main subjects.

Yes, NIOS certificate is accepted by many foreign universities for providing admission in their universities. Few universities may require you to appear for the IELTS. Jobs abroad are also available to students who have completed their schooling from NIOS. Regards.

First, wait for the cut-off. If you cross the cut-off, then decide about college. Until then, you must have to wait. For your reference, I suggest you Graphic Era University for CS & EC. College having best infrastructure and emerging college. Or you may opt Galgotias and so many.

You are eligible to join IAF through NDA exam if you have opted the subjects physics and maths in 12. The exam is conducted twice a year. And, they invite applications around June and September every year. Check the website upscale for more details. If you are selected, you have three years of training in NDA along with people who would be going to army and navy too. After this, you get a B.Sc or B.A. Degree based on what you studied there. Then another one year training in IAF and then you would be commissioned as an officer in the flying branch of IAF.

Yes, Maths is necessary and it is in the syllabus of BJMC prescribed by IP university as Maths related to other subjects directly and indirectly. So, you should focus on mathematics as one of your strong subjects.
All the best for your future.