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What exactly do you mean by "students don't invest, and they shouldn't be taught to do this because they are not mentally or emotionally stable"? What level of students do you think op is talking about or referring to, did he mention that the students he is talking about are nursery or elementary pupils?
OP mentioned starting in 9th grade, and I'm a high school teacher. That's why I can say they're not ready—at least most of them. Unless the OP says it started with college students, I wouldn't argue.
I did not read any where where op said cigarettes affects one's age, and besides, is age an important factor in human death?
Do you actually read?
... but smoking guarantees that you will die very soon.