Nothing wrong with that at all.
Making a giant assumption here, but I wonder if the LW is the kind of person who can not hold a drink, and is therefore judging everyone else by his/her own physical capability to process alcohol ("They've had one drink so they must be tipsy!")
I, for example, can't hold a drink to save my life, so I personally wouldn't have a drink before a school meeting for my imaginary kids because I know jolly well that I'm quite significantly tipsy after one glass of wine, but that doesn't mean it affects everyone else the same way.