Good job on quitting pot at a young age. I'm 32 and just quit last year because it was really holding me back mentally, emotionally, and financially. I quit drinking too. I'm pretty much a teetotaller. As far as abstaining and how its helped with my stutter, well to be frank, it hasn't. I stutter just as much as I always did. But that doesn't matter, because the benefits of a sober, clear mind, and more money in the bank, and a better relationship with people and God is worth having even a worse stutter than before. And don't worry about stuttering in a job interview. What is far more important is the words that you get across, not how you get them across. You can even start your interview off by telling the employer that you stutter sometimes and that it wont be an issue as to your job performance.