Grow guidelines like an 8 wk timeframe are just that, guidelines. At that link When To Harvest at the top of this page there is a wealth of information to consider. IMHO, when to harvest is when the plant says it's ready and has reached max potential. I like mine when the trichomes are cloudy with just a bit of amber.
I am an indoor grower but I would think that growing indoors or out is a matter of personal preference. Or situational circumstances.