There are many reasons why some of the ladies have not started flowering. First one is obvious - unless each one has received exactly the same treatment, exactly the same conditions and genetics ... they will start differently. G13 from experience has really good genetics. Plants are very consistent, but flowering will not be the same. Main factors, from experience, that will determine flowering delays:
-plant in stress?
-soil pH
-availability of light, amount of daily exposure to light
-drought and/or lack/excess of nutrients
These and other factors contribute to the ultimate trigger than sets the plant into flowering. I have a couple with obvious ph problems due to extreme heat (light green leaves), they haven't started flowering but I'm working my ass off to raise ph with dolomitic limestone. Will take a week to kick in.