Do your girlfriends know that you do not drink? A lot of normal drinkers think its easy.. for us.. its not. And a winery is somewhere that I wouldn't be able to go. If they know you are not drinking, they should totally understand, given you will be standing there watching them drink?
I agree with what the poster above said about all the work you have put in, and the AV voice being woken up again, tenfold. ESPECIALLY if you control it. See... I am in control.
Don't let all your hard work go down the drain, for 1 day.