Hi janavi
You can do computer science after 12th commerce but there is certain that if you have taken Maths in 12th commerce than you are eilgible for doing bsc in computer science and you also do Bachelor of computer application and you can do diploma in computer engineering after 12th commerce but my suggestion do bsc or BCA after completing if you can do MCA in top college like NIT Bhopal.NIT trichy and many more where you will get lot of opportunities and exposure and placement after MCA from these is amazing one can except 15 lakhs per annum as average package of these college for MCA student

Hope above information is useful for you

Good luck