You have framed your question in a little vague manner. From what I could get, your final year of graduation was 2018, so you passed in that year, but didn't give exam and in next year(2019) you couldn't qualify.
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.

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