She never existed (see below).
Within the main trek canon (TV + Movies) there are no subsequent mentions of Amanda Rogers or her parents. In fact, the events of Voy : Q and the Grey (where Q describes how there have been no new Q children since the beginning of the new era) would seem to completely ignore her existence.
This apparent contradiction is dealt with in the EU novel "The Eternal Tide". Amanda Rogers is investigating why Voyager and Captain Janeway appear to be doomed to destruction in multiple timelines. She encounters a powerful spatial rift and is unfortunately killed. Not only that, but her entire existence (including her entire timeline) is totally erased, with the Q known as Junior the only one who remembers her.
Releasing those fears and reminding herself of her limitless
abilities, Amanda moved closer to the emptiness. Only then did she
perceive its power over her. Why had she ever feared it? She belonged
to it, and it to her. It was her birthright. It was the most
magnificent, perfect energy that had ever existed. All that was Q
meant nothing in the face of this brilliance. It quietly demanded
surrender of all that she was, and with great eagerness she began to
pour herself into its insatiable need.
It swallowed her whole.
Q Junior is quite disappointed about this and spends much of the novel investigating the circumstances of her death before ultimately accepting that not only was it inevitable, but the result is that her entire existence has been erased:
“She died, trying to help me,” Q replied.
Icheb swallowed the lump that immediately formed in his throat at this revelation.
“I’m so sorry,” he said truthfully.
Q nodded. “Thank you.”
Icheb moved to sit next to Q on his rack. He had no idea how one might comfort a Q, but as he had appeared to him in human form, Icheb acted as if he were talking to a friend.
“I didn’t think the Q could die,” he said, hoping to draw Q out. It was clear that he needed to talk.
“They can, under very rare circumstances,” Q admitted.
If we take the book as a reliable source, then she was unable to intervene in the Dominion War because she never existed.