I had a look, and personally I wouldn't think about harvesting yet. 🌱
I can see what you mean, some of the trichomes already appear cloudy/milky. But looking at the overall bud structure and development, they still look like they have quite a bit of bulking and maturing left to do. Especially if you're only around week 4 of flower, I'd expect at least another 2 weeks, and quite possibly longer.
Also make sure you're checking trichomes mainly on the actual calyxes rather than the sugar leaves, as those can mature much earlier and give you a misleading impression.
I'd be patient for now and let the flowers develop. Watch the buds swell, the pistils mature and then keep checking the calyx trichomes as you get closer. They look like they still have more to give! 😊🌱