no, you have a higher chance of getting cancer at a younger age, and if you decide to quit later on, it will not necessarily be easy, also if you start and then you quit there is the serious possibility of weight gain.
If your 16+ and you do it once, it's fine(my opinion only). And reason is, people can experiment if they want, if they wanna experiment smoking for te first time, hey go ahead. And if they smoke a lot, I wouldn't care cause there not me.
It's not okay to smoke at ANY time of your life. If you're young, you get early non-reversible effects like a head start to get lung cancer and emphysema, a pretty permanent bad breath problem and more susceptible to lung diseases like pneumonia if you get colds or have trouble breathing which can lead you to be less fit.
It's not ok to smoke ever. For teens the chemicals in cigarettes can effect bone growth. Not it height, but in strength. Not to mention effects the chemicals have on your lungs, heart, and brain. Every breath filled with cigarette smoke is one where you deprive your body of oxygen.
It's definitely not ideal but I can't rally judge. Everybody makes mistakes but that's a foolish one to make considering you know all of the risks. My friend's brother is 18 and he smokes and he was diagnosed with lung cancer a few months ago. Lung cancer in teens is very rare, so obviously he had some other health issues that nobody knew about too, but your chances of developing lung cancer in the future are VERY high. Plus smoking makes your teeth yellow, and your hair brittle, you'll also get a smoker's cough and your skin will get wrinkly much faster than others.