Sciences that are very closely related to computer science are mathematics, physics, logic and electrical engineering. Of course commerce can be useful in any field of work but if you want to know more about computer programming, microchip design, computer networks, Internet etc. I believe you should take some of the courses I mentioned above. Not only because you can learn how to use different mathematical operations in your algorithms or learn how transistors work, but also because those sciences require similar "way of thinking" as computer science. So in a way you would also learn how to think as a programmer before learning anything about computer programming.