Hello Ritu, 

You can apply for LLB now as well, because LLB has no age limit. For LLB the minimum required is to have 45% marks at your graduation level exam. Since you are not joining right after class 12, you will have to do the 3 year LLB course. 

You can look here for further details: https://www.google.com/amp/s/law.careers360.com/articles/9564-law-entrance-tests/amp