Since, you have already appeared for PU BALLB, I'm not going to specify the eligibility criteria as it's already known to you, but there's no age limit in terms of appearing for this exam.

A candidate appearing in PU BA LLB 2019 might fail to crack the same in the first attempt. Irrespective of the age and number of previous attempts, he/she can appear in the law examination as many times he/she wants .

You may consider going through the following link for detailed information regarding this matter-

https://law.careers360.com/exams/pu-ba-llb-entrance