Hi Suyash,

          You can definitely pursue CA with a science stream in 12th grade. You need to crack the exams and have a degree as a prerequisite. So you will need a lot of knowledge about economics and commerce streams, which you can achieve in your bachelors or even with an extra CA coaching class. But if CA is your passion then it is advised to take commerce and go with your ambition so that you don't lose track. It is a good ambition and you can work towards it. All the best !!!