Board exam percentage is the eligibility criteria. Percentage is the bar kept by the college to select candidates.
as per your tag:-
eligibility criteria:- Candidate must have secured minimum 50% aggregate in 12th from a recognized board. for reservation category:- 5% relaxation
There is no age limit and for open university candidates, if they don't have basic qualification then they are not eligible for admission.
Selection is done on the basis of score/rank secured in the BA LLB entrance exam.
For more details, please visit the link below:-
Please check PU BA LLB counselling section which will help you clear your doubts.
Hope it helps!