It is difficult to predict ranks in an aiims exam as it is based on the percentile system I.e number of people you have surpassed with your marks.

here is a way for you to get an approximate idea:

https://www.aiimsexams.org/pdf/Final_Result-rank-wise-Nrs-Officer.pdf

This is is a list of selected candidates (2017) with their ranks and marks. Based on this list there is a high probability of yoyour admission in aiims