Pooh & Kakaze, your questions and comments don't make sense because you persist in treating this as a description of real events. Only if you see it in this way does Pooh's question
become meaningful. And it leads to further tangles in that since DEATH couldn't foresee the Auditors plan to destroy the world, than what makes you think Time could either?
It follows that Kakaze's reply
is equally irrelevant.
The questions you need to be asking have to do with why Pratchett has characters acting in a given way, keeping in mind that he at times has them act in contradictory ways throughout a book. Thus, the real important question is why is Pratchett writing about a "race" of "devils" whose ideal world is one of complete stasis? What, in the actions of humanity, might he be parodying. Remember the book was published in 2001, when we had just gone through the madness of Y2K and what would happen if Time stopped at 2000.
Lobsang and Jeremy were theoretically born about a week before time stopped. Yet they were both adults when time stopped. Why were they sent back in time to be brought up, if not to defeat the auditors?
It follows that Kakaze's reply
Time couldn't have had a son in order to stop the auditors, because Jeremy was required for the auditors' plan to work. Therefore, by having son(s), Time was both causing and preventing the event. For that same reason, the event would happen when her son(s) were young adults, whenever they were sent back in time.
The questions you need to be asking have to do with why Pratchett has characters acting in a given way, keeping in mind that he at times has them act in contradictory ways throughout a book. Thus, the real important question is why is Pratchett writing about a "race" of "devils" whose ideal world is one of complete stasis? What, in the actions of humanity, might he be parodying. Remember the book was published in 2001, when we had just gone through the madness of Y2K and what would happen if Time stopped at 2000.