Daria did not become a child of prophecy for no reason. She spends the next two hundred years playing around and inventing various things -- explosion amplifiers, explosion shields, inflatable stone buildings, a branch of growth magic that works for non-fairies, six generations of gaming consoles, a magical variant of the virtual reality Internet -- and she has a great time doing it. What she doesn't realize is how quickly some of her inventions catch on, or the technological revolution sparked by a few of them; she just keeps inventing whatever strikes her fancy, and taking suggestions from friends whenever they request an idea (guess who asked for the explosion-related things).
Sometime after Dron's death, an administrator at the wizarding school comes up with the brilliant idea of filling the hole he left with another dragon who once graduated from their school. Daria's thrilled with the idea of sharing her inventions with a whole bunch of new students, and she happily agrees to go there and teach. She remembers at least half her classes she's supposed to be in charge of, and occasionally even thinks to read the lesson plans the administrators give her. For some reason, this is not quite enough for the administration, and they wind up hiring someone else for the position after forty years of dealing with her.
Following this, Daria and Gavin spend a few years running around in human form in every human country they can think of, since he's in his fascinated-with-humans phase. She loses interest after those few years and wants to return to full-time inventing, but he seems so disappointed that she suggests he go enroll himself in the wizarding school instead, since his mom's ancestors attended there for generations. Gavin loves this idea, so he promptly goes and does so. While there, he becomes great friends with the crown prince of Dragoria -- of all people -- which makes quite a big difference years later, when that crown prince is made king and outlaws dragon-hunting in his country.
Daria marries at the age of two hundred and eighty-three -- long before Cecelia -- and she somehow manages to find the time for eight kids. She and her husband collaborate on many things, just like her parents before her, who were magical inventors (they developed the entire branch of dragon-usable shapeshifting magic), and also like his parents currently (ridiculously eccentric historians who tend to stalk Sages).
Daria's inventions continue to spark technological revolutions every century or so for the next eight hundred years, which delights most people and terrifies most of the ones in power. Five different Oracles make prophecies about her in her lifetime, and eight different nations produce kings who try, specifically, to kill her. None succeed, which has a lot to do with the fact that a particular Oracle keeps dropping by to warn her every time an attack is commencing.
Daria gets very good at shapeshifting to human, human, fairy, Gorgon, and mermaid -- so whenever she outlives one of her old friends, she "disguises" herself as their species and goes off into a different country of that species, hunting for a new friend. She doesn't seem to mind that she keeps outliving them; in fact, her short attention span seems to fit very well with replacing all her non-dragon friends on a regular basis. She also fails to notice that cults of Daria-worship keep springing up whenever she creates a new technological revolution.
She lives to be nine hundred and seventy-eight, and she's always eccentric and happy.