can you give me rough idea plzzzz

It is a relative concept not absolute concept. Just work hard with all your dedication and determination. You will definitely get your desired percentile.
We can't tell the marks because suppose I advice you to score above 80% but the exam comes out to be tricky and and not much candidates reach that level then you'll be in the top percentiles if you scored such, but if the exam turns out be very much doable and easy then a lot of other students may get similar or higher marks thereby lowering your percentile.
So focus on studies and improve your concepts. It's just an exam you can clear easily with practice.