If I may play devil's advocate in this thread...
Don't get me wrong. I wasn't a heavy drinker in fresher's either (2008). And I saved money for it (eating more frugally came into it too). But even though university carries a reputation for excess, many people go through uni and come out of the other end with a fairly good grasp of responsible consumption. I like drinking beer, and lots of it. I don't, however, see it as anything else than another interest, such as football, fashion or computers. I don't need beer to be happy, as I have many other interests, but it does make me happier, and yes, I do remember most evenings when I have a drink. I would also contest the notion that 'saving money' is an inherent virtue of teetotalism any more than not being interested in cars makes you any less inclined to have driving lessons. I've saved money on a phone contract because I don't have an expensive phone. I've saved money on champagne from not being a champagne connoisseur. Etc.
The thing is really you don't have to justify yourself when you don't drink. 'I just don't really like it' suffices to all reasonable ears. You may not like the taste, you may have had a bad experience, whatever. I didn't like the taste at 18 and I do now. It's much better to have your own reasons for not drinking than find pseudo-justifications that are really no more valid than saying 'I don't like it'.