I never started. When I was growing up my dad told me if I didn't smoke or chew tobacco when I reached 21 he would pay me one hundred dollars. He paid me on my 21st birthday.
I bought two packs of 20 during an Easter break from school when I was 14. Smoked 20, threw the other pack away and never smoked again. One of my better decisions in life.
My Dad smoked but once told me he wished he'd never started. His generation thought it strange not to smoke, I think! I tried a cigarette once, perhaps twice; didn't like the taste, realised it's an expensive habit as well as not good for you, and have never smoked since.
@ArishMell I went through all that and smoked on anyway. Started at fifteen quit at thirty nine, now I run a coaching service called Beautiful Quitters