I had a friend that was born on December 30 and she was 18 in Grade 12. (After her birthday, since the school year started in Sept, she was 17 then)
And that driving friend is her classmate?
More likely the author didn't put too much thought, BBQ establishment doesn't check ID, MC forgot she was underage, etc. But just saying it's possible she's 18.
I know some seniors in high school can be 18, I was one. But it doesn't mean that all of them are.
not sure why you keep talking about the driving friend? Maybe he is 18, maybe not, but he isn't the point I'm talking about.
It was quite likely that MC was unaware she was drinking alcohol, as seen in the panel where when she's pouring alcohol, she was more focusing on talking to the male lead, which led her to being drunk as hell.
I'm
assuming MC is underage here, so that's why I'm worried for her.
But even if MC is 18 and ok to drink, there's still the issue of some people seeing this, taking photos of her being drunk and reporting to the school, which can be very bad for her image with the teachers. Hell, they can even say that she's acting like a delinquent to deduct her bonus/extra points, revoke her scholarship, etc.
Source: My country's high schools are very alike to Chinese high schools, I know what I'm talking about here.
TLDR: I'm just worried for her, let me be bro.