I don't drink either, I don't feel the need to. We are similar ages, right? It's my 18th on the 28th (yes, Final day), but I don't know whether to drink or not. I can't actually remember the last time I had a session!
But the main reason for me not drinking has been proven by two situations.
1) My girlfriend spending 2 hours in the toilet getting sick on her birthday
2) On NYE, two of my mates were in bed at half past midnight as they had got sick everywhere.
My mates all say that you have a better time when pissed, but then, who's had the better night not making a clearing in the woods of themselves, getting sick everywhere and I can have just as a good time without it?
Also, I save a shed load of money too.