You don't have to notify your guests that you won't be serving alcohol at your nuptials. Invitees are attending the event to witness and celebrate the marriage, not to enjoy access to alcohol. A few drink options are more than enough, so serve your guests what you're comfortable with. If you want a nonalcoholic affair, try serving something a little out of the norm, such as virgin signature "mocktails," strawberry lemonade with fresh berries on a skewer, or hot chocolate with a sprig of mint to keep your refreshments memorable.