Swapnamoy, Although, it is very difficult to predict the cutoffs and the predicted rank of IIT JAM Physics, but we can make use of previous year trends to calculate the expected rank and cutoff. With respect to the cutoff, it is a big possibility that you would clear the cutoff irrespective of your category as many coaching institutions predict it to be around 16-18. However, predicting the rank is a bit more difficult as it also depends on factors like total number of candidates and difficulty level of exam which  varies every year. However, looking at past few years trends , you can expect a rank close to 300, maybe even less than that based on the variables as described earlier.

Hope this helps.