"When you think it's ready, give it another week." Usually a good advice.
I read somewhere that this is the time when potency is at its peak. Something having to do with milky=THC and amber=CBN (crap that just makes you tired, AKA 'fake stone'). That's why I harvested my last grow when I started seeing ambers, just to test out the theory. It was potent all right. Don't know if it really was because of less ambers or not, though.
I think it's a question of less weed that is a bit more potent or more weed that is a bit less potent. Don't take my word for it, though.
The girls are looking nice!