You need to appear for CLAT Entrance exam to get admission in National Law College. There is no problem with the gap as per the eligibility you should have minimum 45% marks in aggregate of the subjects appeared in the 12th board examination and 40% for SC & ST Category. For further eligibility about the exam you can go through with the given below link.

CLAT Eligibility

Hello Vishal

In order to get admission to NLUs Is you have to appear through CLAT.

And the qualification required are:

Candidates need to have qualified Higher Secondary School/ Intermediate or equivalent examination from 10+2 education system and they need to secure at least 45% marks in aggregate of the total marks and if belonging to SC/ST category, needed to secure at least 40% marks

The application form is available before 30th march you can apply.

Refer the link below  for more information

https://www.google.co.in/amp/s/law.careers360.com/articles/clat%3famp