I want to do b.sc(computers) after my completion of 12th . so what to do now?
Yes career in computer science is a very good choice . There is a lot you can do after your 12th in computer science. To get admission in BSc (CS) you have to find and apply for admission in institute or university. The other alternative courses are liike BCA. BT/BTech (IT/ CS). Check out this link
college for Bsc / BCA courses (https://www.admissionfever.com/coursedsh/cr/326/BCA/1/30)
Best wishes