PM me your final draft and I'll clean it up
how about this: (I really can't think of any anecdotes or funny start)
I am ABC, I wish to apply for PhD in Physics in University of XYZ. The academic exposure in physics that I got during my under graduation both from curricular and extracurricular activities have encouraged me greatly to take up higher studies.
Physics and Mathematics interested me from my very childhood. Right from school I had a habit of solving problems in physics and mathematics with a different approach than what was in the text book. I consistently topped in mathematics and physics from 7th to 12th grade. Due to my outstanding .........