Smoking is very harmful. You can get lung cancer and other diseases. Smoking turns your lungs black and tarry. I know because my uncle died from lung cancer last year. It was very hard on all of us, loosing a loved one to cigarettes.
If you have a dream of being a good athlete, then definitely don't smoke. Smoking makes your body very unhealthy and weak. It makes it hard to breathe. And don't say, "Oh, that could never happen to me, I'm only going to try it once." Well, if you try it once, maybe you'll try it again, and keep doing it and before you know it, you're addicted. Cigarettes have something in then called nicotine which is very addictive. Even if you want to stop, it would be very difficult.
Cigarettes can also get very expensive. If you get hooked and smoke packs a day, that's a lot of money a week.
Smoking can also stain your teeth yellow and make them look ugly. They can also stain your fingers yellow and brown from holding them. Also you and the people around you when you smoke will smell badly. So, as you can see, smoking has no good points. There are only negatives. So I suggest you never, ever try one, because it can turn into a lot more.