You'll still have new pistils shooting out until the very day of harvest. You'll be close to the end when 75% or more of the pistils have wilted...and don't appear to be replacing themselves as rapidly as they used to. Best way, in my opinion, to check for maturity is by getting a close look at the trichomes all over the plant. I harvest when about half of them have turned a slight amber color.

Great looking lady, by the way! Big Bud, I'm assuming?