Some people go straight to 12/12 from the start.

The key to knowing that the plant is ready to flower is by the alternating nodes. If you notice the nodes grow at the same spot to both sides then after it grows up and the nodes start growing one higher than the other, that's the sign that they are mature enough to flower. It really depends on what you want to do. You can flower early and get buds and you can flower later and get more buds.