I "smoked" my first joint when I was 14, but it was some of my cousin's shitty homegrown (I dunno what he did wrong) and it didn't do much to me.
I don't smoke tobacco and so when I first started seriously smoking at the age of 17 I didn't know the whole inhale thing. LOL
So I just didn't "get it" at first, I would get a little high (mostly feel it in my eyeballs) but I wouldn't buy weed because I wasn't that impressed.
Then I learned to inhale, and whoa.
The first time I ever got high off a joint, wow. It was good stuff too, it came out of Atlanta (or so the dealer said) and it was some seriously skunky shit. I took probably 6-7 puffs off one good sized joint, and my world was turned upside down. lol