To me your plant looks well and truly ready for harvest. Leaving it much longer will cause even more THC to break down into CBD and CBN. Once the plant is as ripe as this one, metabolism has slowed considerably, as the plant is approaching death, and the slowed metabolism can no longer support the production of fresh THC to outweigh the amount of THC that is being broken down into CBD and CBN, amongst other non-psychoactive cannabinoids. And as you have already left the plant pass its optimal stage of peak THC concentration/quality, these flowers will probably produce a heavy, sleepy and lethargic stone, which might be your preference, however if you prefer a more "up" and clear and active high, in future you will have to harvest a little earlier than this, around when there are about 95% of browned pistils against about 5% whitish ones. You will find a pictorial representation of when this window of peak THC production is evident in a photo I posted in my diary "cannabis conundrums" and if you are keen to see it, along with other photos of some weird and wonderful things cannabis plants are capable of doing, including hermaphroditic flowers, root systems on a three week old seedling and some genetic mutations amongst others. If you are new to growing, it can pay to do some home experimentation with your next grow and harvest a bud from your plant, when it is nearly ready, every few days (5-6) and sample the flowers at various stages of maturity. Do not smoke them immediately, but record at which level of ripeness they were picked, using say, 85% pistils brown, 90% pistils brown, 95% pistils brown and 100% pistils brown. This is easier to identify rather than trying to guess how much, percentage wise, trichomes have gone cloudy or amber etc. Once you have all four samples dried and cured for a week or three, try them side by side and judge for yourself which level of maturity you prefer. Effects will vary from strain to strain, but this pistil colour method will get you in the "ballpark" reasonably consistently. Imagine that, advice on doing homework that involves smoking buds for scientific purposes! School was never that enjoyable in my experience!! Hope this helps,.... Organoman.