Hii!
Frankly speaking, you can apply for 3 years LLB course after completing graduation, but the eligibility criteria differs as per different institutes. The eligibility criteria states that the candidate must have completed graduation in a relevant discipline with minimum aggregate marks as specified by the respective institute. The admissions are mainly based on entrance exam. So, you must try. But there can't be a surety in it.
Hope you understand.
Good luck!