Hey Riddhi.

National Law University Delhi or NLU delhi does not offer a 3 year LLb course. It only offers a 5 year integrated BA LLb programme, LLM and PHD courses.

So if you a already pursuing your graduation and now you want to pursue Law, you cannot take admission in NLU Delhi as this course is not offered by them. You can pursue law from a University/ Institution which offers a 3 year LLb course.

There are various colleges In India one being Delhi University. It is one of the top institutes offering 3 year LLb course.  Other than that you can also go for GLC Mumbai, ILS Pune, PU, BHU, Symbiosis, JGLS, IIT Kharagpur etc.

Best of luck!