you scored 90 marks in JEE Mains, your percentile depends on the overall difficulty level of the exam and the number of candidates who appeared. However, based on previous years' trends:

For 90 marks, your estimated percentile could range between 80-85 percentile.

This is an approximation, as the actual percentile can vary based on:

The difficulty level of the exam in your session.

The number of candidates and their performance in that particular session.