Nicotine is a very addictive drug and in every way worth avoiding.
I started at the age of 13 because it was considered cool, but it is not it is an awful addiction that I have fought on and off for the next 38 years. I haven't smoked for a bit more than 2 years now but like any drug addict I still sometimes crave a smoke and know as soon as I give in that will be it, there is no such thing as "just this one".
You said you know it is bad for your health, Yes it is and worse you find out the effects years later.
We aspies have few enough friends, I have been watching on of mine die from lung cancer for the past 2 and a half years 
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Wisdom must be gathered, it cannot be given.