To be eligible for giving the KVPY examination, you should belong to Science stream and have to get minimum of 75% in class 10th if you belong to General category. For SC/ST/PwD, it is 65%. So i guess you may not be able to give the examination but It is pleasing to hear that you've improved a lot after your 10th and to be honest 86% in class 11th is a very good score. And you will do even better in your 12th class for sure. You've got a good future kid. Cheer up!!