When I was 15 years old, I used to play soccer. I ended up quitting soccer and wanted to try something new. I was a skinny guy with no muscles. I started to go to the gym every once in awhile. I started seeing some results slowly. Then I started working out with an older friend at the gym. Him and I started working out everyday and I started to love everything about it. After being so determined to work out, I wanted to make huge gains the summer after I got out of my sophomore year of Highscool. I then started working out every single day. Eating very clean, and lifting weights and doing cardio. That summer I put on about 15-20 lbs. It was well recognized when I went back to school my junior year. All the attention I was getting from it, it had pushed me to workout and be one of the strongest kids in my school.
I love it because I can set a goal a few months out and reach it. Bodybuilding is an art, you can literally sculpt muscles overtime. If you are not satisfied with a bodypart, you can do so much to change it. Either increasing your cardio, or even going heavier. You can always achieve if you believe.