my advice: quit both.  im a junior in high school, and i used to blaze and do alot of other drugs, but never drank.  All of my friends who drink get caught literally every week and one almost died with a BAC of .32.  Theres just no reason when your this young to be fucking your life up with drinking and smoking.  I definately lost alot by smoking (my grades are shit compared what they used to be) and because i used to smoke, i went on to other drugs like shrooms, pills, etc.  This sounds kinda wierd, but when i was tripping on shrooms, i saw papa smurf in my room and he told me that i was ruining my life, so i quit.  It was hard to stop smoking pot at first, but its been months since ive touched any drugs, and i feel alot better about my life now.