hey dave...chill dude. You have a minimum of 2 weeks left to go, probably closer to 4 weeks. (8-10 weeks for WW to reach maturity) Plenty of time ti get your loupe, then start checking those trichomes.
There are several important points to consider when choosing the optimum time to harvest your marijuana crop. There are different factors to consider between indoor and outdoor marijuana plants. There is the difference between Sativas and Indicas in bloom duration and final effect.
There is the difference between early and late harvest to encourage head to body high respectively. There is the issue of chemistry because what we are really considering in terms of the ripeness relates directly to the chemical nature and state of the plant at harvest. Last, but not least, is the concept of the window for marijuana harvest, where I will begin. http://greenmanspage.com/guides/harvest.html