I did not drink anything substantial until my 21st birthday, and would not have dreamed of having my parents provide alcohol in our home (even though there was plenty of it in our wet bar, which I could have accessed any time during the many parties we had there, sans parents--but my group of friends was just not into that at all). I don't know what we'll do with our future kids. My own parents were more rebellious than I ever was... I was actually the moral authority in our house as a teenager.
I was allowed to sip from beer and wine glasses when I was probably 5 or 6, but of course it was just very tiny amounts and then I would act like I was drunk, and all my parents' friends had a laugh. I just really didn't care about alcohol until my 20s... I credit that having to a strong, smart peer group that was against whatever the cool kids were doing.