I've heard from many professors that they basically skip those "I became interested in physics at a young age..." paragraphs. They don't want a bio, they want to read about your research experience and qualifications for being a grad student. They also want to hear explanations for anything unusual in your application. If it were me, I wouldn't spend a lot of time writing about it, but I'd definitely mention very briefly that although I had great interest in physics, I got my degree is engineering because of this and that valid reason etc etc.
I would recommend avoiding this at all costs. We are all more or less identical in regards to how we feel about physics and how we came to it. We all thought Relativity/QM/String theory was so neat and had to learn more, we all wanted to be the next Albert Einstein and hoped we could revolutionize the way we understand the universe, we all got weak in the knees when Carl Sagan said "billions and billions", etc. As grae said, your primary focus needs to be on telling them why you will do great in a research setting.
Thanks guys. Really appreciate!