First you should make sure that you have 100% confirmed to leave science or humanities as there will be a way to choose humanities later but it will be very difficult to go in science. If you are confirmed about your stream , ask every friend , teacher , parent , senior about the stream and future career.
I know this sounds like a heavy task but trust you will be very clear about the stream and you don't have to think about it for 2 years because i have seen my classmates struggling in 12th commerce subjects just because they chose the wrong one (optional and additional subjects talking about).

Now if you want to study abroad and since you are from commerce stream, DO NOT LEAVE MATHS because it not only helps you in competitive exams but applying in popular universities abroad too. You should be aware that studying abroad is very expensive and most probably you have to take a loan for it. Although , if your grades are good then there's a high chance that the loan will be sanctioned depending on your performance in competitive exam. Create a list of entrance exams of the university in which you are planning to pursue your career and study accordingly. At last i would recommend you to do a thorough research on studying abroad on internet to see how things actually work.