Hi Mayank,

Your marks in school and graduation cannot decide your score in CAT exam. Your academic scores are good enough to make you eligible to apply for CAT. If you wish to see how much you can score in the exam, try solving one of previous years' CAT question paper and see where you stand. This is the best way to know your CAT preparation level. 

September 26, Today, is the last date to apply for CAT 2018. The exam is on November 25, 2018. 

Good luck.