Pre-Flower

How long does it take before FEMALE plants start to preflower? i know male plants are much sooner

Typically males show within the first week and females generally follow 3-7 days later. So about 2 weeks (some sooner) from the start of 12/12.

Depends on the strain, and how mature it is pure sativas dont take as long to mature as a pure Indica, if you have had it in veg for 4 or 5 weeks it should show preflowers in about 10 weeks. Two of my 5.5 week old AK48s are already showing female preflowers and I havn't cut the light back to 12/12 yet, it's all about genetics.