Normally, the formula to calculate the percentile is

Percentile of a candidate = (No. of students scoring marks more than or equal to that candidate) / (Total no. of candidate) * 100

As you will not be having the data of " No. of students scoring more than or equal to you ", you will not be able to calculate your percentile by your marks. However, the reverse way is possible i.e., you will be able to calculate the number of students scoring marks more than or equal to you after you get the percentile score from NTA.