Should cigarettes be illegal for anyone born after 1989?

Question

then in a few decades no one would smoke anymore

Answer 1

Look at the illegal drugs that people use. Do you remember a little something called 'Prohibition'? How well did that turn out? I may not like smokers but to ban it would be idiotic. I hope you weren't serious with the question.

Answer 2

Approach it from a different direction.
Try this: tossing a lit cigarette butt from a car window leads to confiscation of the car for a period of 90 days.

That'd probably lead to smoking cessation without the perils of Prohibition.