I think it's a misconception that your body doesn't let you get high the first few times you might smoke. I'm pretty certain that the reason people don't get high their first time smoking is because they don't inhale correctly. Just think about how much more efficiently you inhale after all the practice we have all put in to smoking. Smoking cigarettes before trying weed would give you previous experience in inhaling, even though you smoke cigarettes different than pot, it at least gives you a reference point.