My goal in life was to always wait until I was 21 for my first beer. Had my first one with my dad a week before my birthday, because I had plans with the boys for my birthday. Bad breakup when I was 21 caused me to basically not give a shit about much for a couple years and got a good solid drunk 3-4 nights a week with a couple buddies. Not sure I'd call it blackout drunk, technically, but my memory is spotty of the 2 and 5 hours or so of drinking before my buddy and his fiance taking me home from downtown Omaha at about 11:30 at night. Can't remember if I was 21 or 22. Apologized to everyone the next morning and haven't been near that since.
Anything after 25 and it's like come on man, in my opinion, but anything after 30 is embarrassing in my opinion, to get blackout drunk. Only occasions I can get behind are the boys trips every year or couple years, or Bachelor parties if you're on a trip.