The problem is, there is no "when" here: nothing is real, nothing is forbidden - period. Whether we like it or not, whether we accept it or not, such is the actuality of our existence. People are overwhelmed with chilling, devastative, abyssmal existential horror - almost literally terrified out of their minds - when they truly and fully comprehend this ultimate truth and all its implications.
No surprise that most of them - nearly all - thy anything they can to exlplain it away, to dismiss it, to forget it, to do anything not to continue looking into the Abyss that lies beyond all veils of illusions.
But a very few who withstood the horror, who did not turn away, obtain the absolute freedom. Since - as they understand it now - their Selves is their own creation, this is, their Selves create them-Selves out of the Void with their own free volition. They understand that their life is their own act and choice, and each act they perform and every choice they make is true, beautiful and good, as long as it adheres to their own path of truth, beauty and goodness, one that they willingly created and chose for themselves. And there is no external arbiter, no judgement from above or from outside, no permanent criteria to cling to and no compulsory prescripts to follow - no "God", no "Nature", no "Logos", nothing and no one whatsoever to obey - to which they should submit their own path. Their only arbiter, their only judge, is the path itself, this is, their own conscience - which is the manifestation of this path, and thus of their volition. And, from this path they form their own individual ethics, aesthetics and episteme, ones that are not forced on them, but a gift of their own innermost beings. Being such, these ethical, aesthetical and epistemic principles are not a restriction of their wills and Selves, but the truest expression of them.
Such is our existential freedom, simultaneously horrifying and blissful as it is, the freedom of beings who are perpetually create them-Selves out of Notningness.