Hey aryaman

63 percentile means 47%students are ahead of you.means if 10lakhs students are appearing than nearly 5 lakhs students are ahead of you.

And this is very big number.

You need a lots of improvement work very hard .

And you have still 2-3 months with you prepare well with full concentration.

Good luck

It is difficult to predict your exact qualifying marks or JEE Advance Eligibility as first time JEE is being conducted twice and rank will be based on NTA percentile score. 

If you want to know teh expected rank you can use this formula to calculate your expected rank-

874469 are the number of candidates appeared for the January exam. So rank formula is (100- your total score) * 874469 / 100.

If the number of candidates for April exam increased to 1400000 then your final rank shall be (100- your total score) * 1400000/100.

Good Luck!