Go by the color of the trichomes. I check trichomes in 3 different spots.
The top…they mature faster than the rest of the plant as it gets the most light.
I then check the middle and finally the bottom. You can always harvest the top first if its where you want to be and enjoy.
In reality, you have a few more weeks to go. I made the mistake of using the color of the pistils when it was done. I don’t make that mistake no more.
Also the time frame the breeders say is in perfect conditions and as home growers we don’t have their resources. I have found to add about 2 weeks more than they say. I hope this helps.