I`m sure there will be no problem, have seen many over the years who have been borderline and have never seen anyone being refused a drink. Pretty sure, unless you are falling about the place you`ll be fine! Leave that to us older ones!
I can't remember exactly as usually bought as part of a meal and then I was too far gone to take note. All I can say is that it works out so cheap it's shocking! I'm going out the week before you so will find out if it's still the case then.