Going on a date FOR 'happy hour'. That kinda implies that you're going there to get sloshed. (British term for drunk). Go somewhere just for a coffee. Or say 'i'm not drinking tonight cos I'm already intoxicated by how beautiful you are' haha or 'i want to keep a clear head so I can appreciate your beauty.' Hehe. Don't lie though. Silly white lies at an early stage aren't a good idea. And if she's not beautiful, tell her. Women appreciate honesty, haha. Seriously though, do something where alcohol isn't an option or just say 'I'm on the wagon and I feel I'd be letting down the guys at AA if I had a drink.