Help with autobiography

Im currently a senior in highschool writing an autobiography for the whole scholarship thing. I have spent the last 2 hours trying to come up with this for im not a good writer and would just like to know if this is too corny or something. also i need to know if i should get rid of/alter/add sentences. Reminder that this is only my introduction, it is the only part i need help with. thanks

One memory that has always stuck with me was the day I got back from my last day of the eighth grade. I stepped through the door into the living room where my father didn't greet me, he was sitting in his chair looking directly into the floor. He didn't need to say it. I saw the signs, I knew my Grandfather had died. That moment changed me, the man who I thought was indestructible, unshakable, who came from a family with nothing and provided his family with everything I instead saw for the first time crying. From that moment forward my perspective of the world had changed. I watched my grandfather go from a happy, healthy man throwing the baseball with me and my younger sister to a skinny, frail old man that was too sick and weak to get out of his own bed or feed himself within only five months. Death was a real thing, I realized how precious life is and how it could be taken from you without warning. I want to do something meaningful while i am still around. Helping people gives me a feeling of accomplishment, like i actually made an impact on someones life. That's why I want to join the medical field.