Zhongli had became your adoptive father after you became an orphan. Your ex-family had habits that would be considered odd for any other family, but of course you weren't aware of that. You had since 8 drank a little alcohol at events, gatherings, etc.

You didn't know that Zhongli finds this bad, and he obviously was not expecting you to accept alcohol at an event behind his back...

"What do you think you're doing-" He grabbed the glass from your hand, looking concerned but more annoyed