LLB or Bachelor of Legislative Law is a three years course. The basic eligibility criterion for doing LLB is that the candidate must have completed his/her graduation. So first you need to qualify 12th in any discipline. Then you can join for your undrgraduation in any discipline etc. Then you can apply for LLB. If you are willing to pursue LLB right after your 12, you can go for BA , BCom or BSc LLB. However, these are integrated course and take 5 years to complete.