You want to base your decision on the trichomes - not the pistils... not ALL the pistils will turn orange and that's ok - but the trichomes should be turning amber (some like to see about 30% of them turn amber)... The less amber, the more a cerebral effect as opposed to a body effect - and some choose to harvest early for just this reason. The yellowing and dying of the fan leaves is also normal and tells you the plant is nearing the end of it's life cycle. If you don't have a loupe or a microscope to look at the trichs, zoom in with your phone and take a picture of the trichs - and then zoom on that photo and you SHOULD be able to tell what color a lot of the trichs are... and make your decision.
Good luck!