In the context of 23 year-olds, I think it's safe to say that none of them are actual alcoholics, just that they drink A LOT, as many people at that age do.
How is that safe to say? There are plenty of 23-year-old alcoholics, having lost control over their alcohol consumption, in full-blown physical and/or psychological addiction. You don't have to age into it, or take a test, or carry a card. It just happens to you.