Hi Anjali, it is hard to predict your exact marks with your percentile because there were various factors kept in mind while calculating your percentile. Your percentile score is calculated after normalisation in which the difficulty level of your paper was compared with the difficulty levels of other papers as well. As multiple papers were held this time, there was a possibility that some papers would be tougher than the others and hence the normalisation procedure was introduced, also the ranks will be calculated according to you percentile and you need not worry about your marks, your percentile is the main key to your selection to any college. Also even for calculating your rank you need to wait until the results of April JEE mains session are announced as the best score out of both the sessions will be taken for the students appearing for both the exams and then the ranks will be announced. If you want more information about the normalisation procedure you can check out the following link-
https://engineering.careers360.com/articles/jee-main-normalisation-process-how-scores-are-calculated
I hope this would have helped you. All the best!