First time i smoked pot was 16 when at a school party. Was already drunk at the time, don't remember it having any effect on me really, don't really remember much of the night though.
As to a gateway drug, i have no interest in taking anything other than cannabis so i guess that's a no from me. Well i take that back. The only gate it opened was that which caused me to become a cigarette smoker. In the UK, partly because of "tradition" and the fact that it's too expensive to smoke as it is (there is no pipe and bong ulture over here other than for hardcore stoners, it's joints or joints normally) so it is always mixed with tobacco and as such, oh hiya mr nicotine craving. Maybe it's all a government orchestrated ploy to get us addicted to tobacco and paying lots of tax on it
I know while a lot of stoners in the UK won't smoke cigs, they also won't roll a joint without tobacco even if they have enough weed to justify it.