Hey Manoj.

See the marks u have scored is enough for some of the average NITs to pursue ur career in the computer stream. U can opt other good branches in the NITs. Right now it not possible to tell u which colleges u will get as cutoff can't be decided in the new way of marking scheme of the exam. Wait until the NTA provides u the rank list of JEE MAINS. About the percentile score u can use the given formula to calculate ur percentile.

Marks : (100-your percentile)*876649/100

Hope this helped u. Ask if any query

Good luck