CA

Ahmedabad, you can go and do your CA preparation.

Try for One more attempt in November.
If you are dedicated toward CA, then you can definitely achieve it.
If you want to drop it, then you can go for MBA provided you do MBA from a good college so that it would be better for your future and Career growth.

If you are good in accounts and its basics then you can go for CA otherwise go with MBA as it will add more value to your profile and you can choose the specialization according to your interest.

To become a CA after class 12th first, you have to take an entrance exam that is CPT and you have to clear it and go to the inter that is IPCC and that is approx after 1 year of CPT and you have to clear the first group of IPCC to become eligible for 3-year articleship and after that final.
It's approx 4.5 years process provided you clear every exam in the first attempt.
Best of luck.