Something to think about when sexing seedlings...
Force flowering a sexually mature seedling (or its clones), will always give you a better yield, and higher quality, more potent buds. But some ask, how can I wait so long for my seedlings to mature before I force flower them, my growspace only has enough clearance for three foot tall finished plants.
Suppose (for the sake of arguement) that someone grew a seedling, and struck some clones from it when it was about "one month old". Keeping in mind that the clones are the same age as the plant they were taken from, the clones are also "one month old" on the day they cut from the donor plant.
There are no hard fast rules, that say that you can't have clones in vegetative growth, "vegging to size", while you are waiting for the donor seedling(s) to reach maturity and show its preflowers. Once the donor seedlings have reached maturity, your (same DNA age) clones would be ready to flower, and can then be vegged more, to the desired starting height, or flowered.
By the same tolken, you could also force flower the seedlings to hurry the process along while the clones are still vegging, but if you do that rush you'd still need to wait for sexual maturity to show on the clones.
So its easy to see, that it is very simple to have "almost ready to go" mature clones with very little or no time lost, "while you wait" for "preflowers" and "sexual maturity" of the donor plant. And all the clones "can be" at the flowering height you desire. It will only take a few weeks longer, and the results are well worth it.
ps...dont forget to label your clones & moms.