I complete my graduation 2018.bt I can't give the exam.2018 is my final year of my graduation.Next year again I fill up exam form bt I fail.
I'm not getting into eligibility criteria and all, since you have given this exam, you have better understanding regarding this matter and most certaily, you fulfill it too.
Now, coming to the most important part of your question-
I don't think there's any restriction regarding number of attempts for IIT-JAM Exam.
Nor does the official website or even the notification provide any such inputs.