Beginning of week 6, like said, not ready. Get that scope and start checkin' trichs. I feel ya on wondering though, i just recently went through the same thing myself. I had 50% amber hairs by 4 weeks in and got VERY confused, because at the time i was under the impression that hairs were the way to tell. Boy was i wrong. After a full 12 weeks of those girls still going, i actually ended up cutting them down (and that was still at least 2 weeks early, probably due to stress) because i needed the flower room for my vegging girls. Start your counting from the first day you saw pistils, and start watching closely around week 7 or so. That's where you will get the plumping of nugs, the more speedy trichome transitions, and then its just deciding what kind of high you want and determining your harvest day from there =D