How much longer before I should harvest?

Its looks like you have awhile my friend. That plant look young and immature. Id guess at least 4+ weeks left.

The pistils are still white and young, probably gonna be a couple weeks at least. But those are not a good indication. Look at the trichomes for harvesting. A cheap jewlers loupe does the trick. I found an electronic microscope on amazon for like .00. Gives me a super clear view of what the trichomes look like.