Hello canna_mama, There are 2 methods to see what the best time for harvest is.
The most accurate method by far is to use a x60 - x100 pocket microscope to look at the trichomes. Those things are very cheap and it is really just the only accurate way to see when the plant is ready. The trichomes got 3 different colors, they start clear as glass. Then they become cloudy and milky white. And when degrading they become brown like amber. When 80% of the trichomes is cloudy then the plant is the most potent and ready for harvest!
The second method is to look at the pistils (the hairs). When 80-90% is brown then the plant is ready for harvest. This method is waaay less accurate than the trichomes but the second best method.
Enjoy your harvest!