Well pics would help us to know if the plants were in preflowering.

The plants can double, or even tripple in size, so you wnna do it before they good too high.

I'd say put them into 12/12 now and in 1 -2 weeks you'll know what ones are females and what ones need to be cut...

Just make sure you dont run outta room, and make sure if the plants doubled the tips dont come anywhere near the light, otherwise you'll burn up your main colas