How long should someone be in an acting school?

Hello, i just need a quick training, but I would like to know how long would someone have to be in an acting school because I see that they have seminars and workshops for just a day and they have classes up to 9 weeks, is it ever a year of acting training? What's up with it? I would like just about 2 weeks of training....is that good? P.S. I'm 16 years old and i've had training for at least 3 months during the summer at Goodman theatre...is that enough for me?