Teaching our kids about not smoking

My daughter is only 4 1/2 and when she sees people with cigarettes, she points it out to me and asks why they do it.  She knows from previous discussions that smoking is bad for you, so now she is wanting to know that if it is bad for you and people know this, why do they still choose to do

it?  I am afraid that if she sees others smoking, she will think it can't be such a bad thing.  In her timeframe, they look ok while doing it.  Can she understand that they may get sick years down the road and will this be enough for her to be opposed to it? 

What we say and do helps form our children's decisions down the road.  I think next I will explain to her that some people may not have been taught how bad smoking is for you and they made the wrong decision.  When she is a little older, I will further explain the health and medical implications so that she can better understand and be more educated.  Then, we can only hope for her to make the right decision.