She clearly wants him to say "I don't want you to drink without me when there's other guys around" because the guy doesn't properly show a bit of possessiveness, she's not actually going to spend time with rando dudes since she loves him that much
Impossible for him to act like that consider he was like at least 3 year younger then her ...( Only male in otome series that normally act like that )
And I don't think she will want drink Infront him consider on how bad drinker she was ( to point his big sister know about it ) ...and I very confident she can't even hold for 1 week without drink ...left alone hold for another 2-3 year if want wait his legal age for drinking