Two things:

Drinking, if moderated, is not necessarily bad thing. 1st time is always bad, but if you continue slowly, you'll get used to it. You don't need to drink really hard stuff right away. Start with lighter liquor like beer or cocktails.

Two: Be VERY VERY VERY careful as to what people add or give. Trust me, you were luckier nothing bad other than a worse than usual hangover. But you can imagine what all such events can lead to. Drug addiction, embarassing thing, even unwanted sexual experiences... (lol.. yea I know a lot regarding all this!).

Also, whatever you take, always take in small quantities. Never half a bottle!