The continuum fallacy proves there are things that are continually developing so we can't set a value that's true/false on them at a definite point in time. It's impossible.
It's obvious Fred has a beard 4 months in and that he doesn't have one 2 weeks in. But where do you draw the line? You don't because you can't.
At 2 months in, some people would say yeah, that's a grown beard, others would say no way that's a full grown beard.
Sure, but that doesn't change my original point.
If we set the cut-off before the process has even begun, before we have even started working along the continuum, then there can be a clear consensus.
In your example, Fred doesn't have a beard at 2 weeks, but he does at 4 months. Anything between those values is on the continuum, and therefore up for debate. So let's set the cut-off at 2 weeks, as there is consensus that that is not a beard.
The structures which are needed to provide consciousness are not present at 24 weeks, but may be present by 26 weeks (note, still not consciousness, just the structures needed for them). Anything between those values in on the continuum, and therefore up for debate. So let's set the cut-off at 24 weeks, before the continuum has even begun.