Hi Kafka. I agree with others in that you should have a plan as to what drink you will order before you get there. Or how you will respond if someone wants to buy you a drink.
Since you are new in the group, they are probably more likely to respect the fact you don't drink. At least one would hope so. If you were meeting a group that knew you as a drinker in the past, they would probably be more likely to bug you about it. I honestly don't think you'll have a problem. Let us know how it goes.