Am I 12 for thinking cigarettes are bad? Why?

No, it's the way you say it. Less, "Cigarettes are baaaaaaad. If you do them you're baaaaaaaad." More, "Dude, there were so many smokers out today. Maed meh all :(." Most of my friends smoke (it's what you get for going to an engineering college, a little bit of stress there) and as soon as you preach to them that gets them to go off. If you just level with them instead, you'll get further.

I posted valid reasons on why I dislike smokers, and why I think they're dumb. Because in my opinion, smokers are dumb. Again, just my opinion.