I was about 16 when I bought my first weight set. Later I had a coach, but he had a history in power lifting and wanted to mentor me in strength training, but I was more interested in building muscle mass fast. Anyway, I was in one power lifting competition and won. Then I moved away and have kept up with training (my way) ever since then. I was really skinny as a kid...weighed about 102 in my late teens, but I worked out regularly, drank a quart of milk every day and put on muscle.....Then later on somehow I ate too much and put on a lot of fat too...so I had muscle & fat....(I know what it's like to be at both ends. The skinny end and the heavy end)...a year or so ago I decided I wanted my ab muscles to show, so I cranked up my intensity, started working my abs out (which I never stuck with doing before) and cut back on my fat intake. I lost 30 Lbs and am seeing my abs come through. It's a lot of work, but it's cool to finally see my abs. I'm not all there yet, but it's gettin there.
I've always liked working out because it gives you something that most people don't have. It takes work to build muscle and most people won't do what it takes. In fact, probably most who start don't keep at it very long.