How come I don't puke anymore when I drink well beyond my capacity?

This is just out of curiousity. I've noticed that in the last 3 or so years I haven't boked from alochol, regardless of how much I drink. Like when I get super smashed I'll just p out. I find this odd as when I was younger (12-15) I would boke when hammered. My friends ususally still boke when they get obliterated so I'm just wondering if there is any reason why some people wouldn't or maybe it's just different people react differently. But from about 16 to now (18) I just haven't.