I am now 21 years old, and had my first orgasm at 12. This happened by accident.
At the age of 12 I used to get erections and did not know why or how to get rid of them. One day I was laying on my bed reading a book and got an erection. Because I was laying in the sun I decided to just pull my shorts and underwear off and get all tanned. It didn't take long before I was as hard as I have never been.
About ten minutes later I noticed some clear fluid leaking from my dick. Five minutes later I experienced the most awesome feeling of my life and white liquid started gushing out of me. I was worried because I didn't know what had happened.
It was only after reading up on it that I understood that I had orgasmed and ejaculated.
This started me on masturbation and mutual masturbation. These stories are still to follow.