spot on ime... like green said, once she's ready, you'll simply know by looking at her, idk, the entire plant will take on a different look, and once you see it, you'll never be asking if a plant is ready again..
of course lots and lots of people chop early, but idk, i've made that mistake once, and i'll never do it again.. the bud was decent, but no where near as good as it would have been if say i'd of given them another three weeks or so..
the pistils will recede, you might get slight fox tailing starting, the calyxes will be super swollen, and like i said, the entire look of the plants will change... that's how i like them now..