Honestly, it's not that big a deal. I drink every once in a while, but never to the point that I'm too drunk to function. Most of the time I only drink to get a little buzzed cause I'm pretty shy and drinks help me come out of my shell a bit, but I've often been the least drunk person in the room, and I've also been the sober friend. Truly, you don't need drinks to have fun, and most people are not gonna force or peer pressure you to have a drink if you don't want one either. There are plenty of uni events that don't involve any alcohol at all and they're a blast so don't worry if you don't drink. Lots of people don't.