To early.

You still have a long way to go, anywhere from 3-6 weeks. Harvest at 95-98% brown pistils for prime cannabinoids and peak THC, producing a mind bending high. Harvest at 100% brown pistils if you prefer flowers with less THC and more CBD and CBN, that will then give you a dreary couch lock type of stone. Depends on which type of effect you prefer! Get high or get stoned? The pistil colour method is far simpler and more reliable than the "trichome colour method" which has many flaws. I have been using the pistil colour method for 30+ years and can vouch for its effectiveness. Where the trichome colour method fails is that some strains will never have amber trichomes and other strains may have 75% amber trichomes after only 4 weeks of flowering, meaning some people are harvesting (out of desperation), near dead plants, because they have been waiting for the magical "30% amber" to occur, and harvesting at only 4 weeks would produce flowers with very little THC, so this is where the trichome colour method falls down. So as Papa_T said, you really don't need a loupe, but if you are really concerned, a magnifying glass will do the same job. However, the pistil colour method is more accurate, as pistil colour will actually be an indicator of plant health and it is plant health that determines trichome cannabinoid composition, whereas trichome colour on its own does not indicate this at all. Hope this helps, Organoman.