The studies showing that moderate drinking is good for you are very suspect. The evidence on the effect excessive drinking has on your body is very solid. There is a growing concern that there really is no beneficial amount of drinking and it may all be harmful.
As for age, the main difference is that when you are young, you can digest the booze better at night. When you get older, you will pop out of bed about 3 hours after you fall asleep when your body tries to process all the sugars in the booze. When you are younger, it does not take as much booze to start feeling good. When you are older and have been drinking for a long time, you will put down a bottle of wine at dinner and feel nothing. And when you are older, too much booze will go right to your waistline. When you are young, you can drink every night and be at race weight.