A lot of times the decision is half of the battle. I don't drink or smoke either, and sometimes I worried if I would be accepted because of that, but in the end I decided to just not do those things for various reasons. Firstly, because if I got drunk that meant I'd be sort of losing control and might do something stupid. Secondly, I'm prone to addiction and figure the best way to not get addicted is to never try it. Thirdly, drinking in excess and smoking are not healthy.