Hiya there!

The 98.5 percentile that you have received is truly a good percentile score. But you must know tgat the percentile score is not your actual raw score percentage of the conducted examination. The percentile score is the percentage of people who have scored the same score as you have and those who have scored lesser. But still though, higher your percentile score higher is your chance of getting a good rank. Considering your percentile you might have qualified, but I cant say for sure though because the cut off has not been released and it depends on many factors.

On preparing for the next jee mains examination, the core idea is planning.

with precise planning and solving previous year problems with solutions you can develop the idea of the paper pattern and deepen your understanding of concepts

good luck :)