How'd I wake up one day a two pack a day smoker?

I'm 26, started at 14 ... I'm kind of a fun laid back sort of guy that doesn't take life too seriously ... but still how the eff did I wind up a two pack a day smoker? My buddies, relatives and on and on mostly smoke, I enjoy it so don't wanna quit but I at least want my lungs to last awhile, you know