I'm 21, I started drinking at nine (young I know) and it gradually progressed to me being a 19 year old who was getting wasted nearly every night. Getting arrested (three times), getting into a nasty car accident and several small ones, and dragging myself to work hungover every day didn't snap me out of it until I was a few months shy of 20, when it finally started occurring to me that the way I drank was indeed, not normal. I tried to get sober and succeeded for awhile, relapsed after a few months. Tried again, even nastier withdrawal then the first, and made it to nearly six months, then relapsed again with a vengeance, started drinking even more heavily then before and also experimenting with other drugs (benzos and opiates mainly).
But I think I've got it right this time.
Best wishes to all on your sobriety