Girl wants to meet for drinks but... I don't really drink WHAT SHOULD I DO?

Here what I'd do, since I'm not a big drinker either. I'd pick a place to meet her that has some sort of activity you can do there. Play darts, shoot pool, trivia game, shuffleboard, bowling or whatever. That way you can let her order her drink first, then order what you want. Whatever it is a coke 7up or even alcohol. Then you can go & play something & it also helps to have something to do since it take the weight off of small talk & will pass the time so you don't sit there worrying about what you have to drink or not drink. It also helps to break the ice. Let the night take care of itself. If it's a bad date you can move on & forget about it. Bad dates are what makes good ones that much better.