It's 18 here too, but way too many I know started drinking and/or smoking when they were as young as 13-14.
The sad part is that many parents know/knew that their underage kids are/were drinking but they kinda let them continue without really doing anything about it unless it's clearly affecting their studies or their health.
Heck, I even remember my younger brother telling me that two of his classmates once showed up at school drunk one day because one of them was turning 15...