How important are class 12 preboard result? Cbse indian student

I feel my overall profile is good, with a 96% in 10th ICSE, 85% in 11th CBSE. My 12th preboards havent been so good, i scored 78%. But the % of the whole batch is like thay, as our school keeps tough papers and I am still 3rd in my class. I wanted to know will my chances significatly drop due to the marks in 12th preboards.
Ps: my school counsellor told ill be getting predicted in 90s.

Make sure your counsellor mentions the fact that the pre-boards are tough, and that despite scoring 78% you’re still 3rd in the class in his/her recommendation and Mid Year Report(if submitted). It shouldn’t really be much of a disadvantage then.