I have done (hold the applause) 3! That's right three grows with 12/12 from seed.
They all usually take off in growth around week 4. (Week5 if you count germination) and flowers not long after that.
With my indicas I have noticed that after the seedling stage, each node takes approx one week to grow out with the next node peeking out. So one could guess the plants age within a week lol. Anyways.
I have a little black indica from CKS I started ~3 weeks ago with 3 true nodes and just starting her fourth. So she is bang on with my observations. She is about 4" tall (give or take) and quite stout and bushy for being so tiny.
What you will notice as growth behaviours and tendancys will be determined by your quality of seed, choice of medium and nutes, your measure of lumens/lux, and over all care of the plant. Get to know your gear and plants and soon all these questions will he answered.
Indica dominant usually take ~8+ weeks after preflower or 12/12.
Sativa dominate usually take ~9-11+ weeks after preflower or 12/12.
But I hope I was able to give you a comparason. And best of luck with your harvest mate.