Got 97.5 percentile will I be able to get nit core branches..?

It would be difficult to provide you the exact information about the qualifying score & admission possibilities as For the first time JEE Main is being conducted twice by NTA.

Based on this score your probable rank will be 26,846 - 30,846, With this rank the chances are there to get a seat in NITs but less chance to get the core branches. You can check your other admission possibilities with JEE Main college predictor tool.

https://engineering.careers360.com/jee-main-college-predictor

NOTE : Rank Predicted is on the basis of the expected total number of students i.e. 1152650 appearing in the JEE Mains April Session.

Good Luck!