I was a late starter.
I had occasional drinks in my teens but really didn't like it. I got drunk once when I was 19 at a party and got really sick from the hangover that I would not go near it for almost ten years.
Around thirty I started with beer because someone handed me an apricot beer and said "try this, you might like it." I did. I then liked other beers too, A LOT. It was almost like an instant desire to consume too much in one sitting.
I drank on again off again for the next seven years, binge drunk two or three times a month.
Sick and hungover for two days afterwards.
Its progressive...reading this thread all the way through will confirm that. Who knows what I would have become, but I shudder to think because it would probably be true.