I disagree. You'll have plenty of time for learning, for thinking about the content of your studies, for the library, for dedicated focus
later. You're only young once.
Now I'll agree that getting wasted every weekend is a very bad idea. You will end up dying a painful death very early in your life. But it's a good idea to go to parties. It's a good idea to have fun, to live. Doing what everyone else is doing isn't always the best advice, but sometimes it's the best advice. You have to use your (unimpaired) judgement. I wouldn't have half the friends I have now if I hadn't spent nights puking right beside them. Now as an adult with a professional job, if I want to make new friends, the only way to do that is to have kids and set up playdates. Instead I find myself studying, reading books on the couch next to my wife. When you get older, you lose your ability to party like a college kid. You lose the opportunity to have that kind of bonding experience with your peers.
Young people drinking is a serious issue. You're right, it's harmful to brain development, it gets people in all kinds of trouble, and it can be seriously deadly to the drinker or to someone else they might meet while drunk. That's what makes this really hard to write, because to be honest, I'm not a drinker now but I was in college. And I attribute everything I have to the nights I spent not in front of the books, but in front of the crowd, dancing with a lampshade on my head.
So don't drink. You don't have to. Don't do drugs. Don't put yourself or others at risk like that. But seriously, if you're in college DO SOMETHING SOCIAL. Don't, DON'T sit in the library while your youth passes you by. Sit in the library Monday-Thursday. When Friday rolls around, go hang out with your friends. Because trying to make college-style friends as an adult is 100% impossible.