hey there,no they are not ready just yet,still keep looking on calyxes when checking trichomes,thats the best indication,at mid section of the plant you want as much as accurate readings as possible ,your plant ripens differently ,plus it is easy to tell just by looking at the hairs,she is not ready,still in mid to late flower development at this stage,you need curled in hairs .
One main reason your girls are slowing down a bit or better said,slowed down is because they had a bit of over feeding ,seems a sativa kind of phenotype,so i would advise flushing her with 6.0 ph which i say it is a good spot for coco ,be careful with that too,because coco is easier to starve,so a bit more feeding would be needed before harvesting,still i say around 20-25ish days,go with the flush,be careful on the nutes and you are safe ! happy holidays