ipmat indore interviw how to explain the percentage drop from 90% in 10th to 70% in 12th

I am a PCM student and I am preparing for IPMAT this specific question is my biggest fear right now so what would be the best way to answer it

edited: the reason for my drop was that I wanted to be a pilot which required me to score 65% so I thought voila I can score that in my sleep that's why I parallelly started preparing for my ground classes in 12th standard after my 12 I was determined moved from my city to Mumbai and even started my ground training. there was a DGCA medical test I had to do but it seemed like a formality as I am healthy and even athletic, I started the process after moving to Mumbai but it turns out I have a genetic problem related to my ear I can't hear a certain degree of sound and now world came crashing 8 years of dreams, hope not even a breakup could have compared I packed up move back to my city and started preparing for ipmat (I scored 70% because I just wanted 70%)

ps: before someone comes at me saying you should have done the medical test earlier 1. I thought.... believed I am super healthy 2. The certificate's validity was 2 years I needed it to be valid when I started my flying 3. It is an expensive process you need to schedule it after considering everything (please please can someone answer me now)