Let us first consider the canon pairing of MarchexRitz. As such, some deeper conjecture is required to read from the game what may actually have transpired. Unfortunately, the ending of FFTA is quite ambiguous and fleeting on a number of points, not least of which are whether the protagonists remember anything of being in Ivalice (later confirmed by FFTA2). The events of Ritz's life as portrayed in Final Fantasy Tactics Advance paint a fairly optimistic picture of Ritz's fate, and the player has no reason to suspect there is any further significant conflict in her life. Upon returning, Ritz was seen to have done so at least enough to stop hiding behind hair dye, although she toyed with the notion of doing something extravagant with it such as dying it green.
Just before the world reverted, her Viera comrade Shara told her that white hair is considered a blessing by the Viera, which encouraged Ritz to accept and embrace it. She thereupon agreed not to interfere in Marche's attempts to convince Mewt to let go of Ivalice, saying "a game has its end". Although she helped Marche on a number of occasions, as soon as he made significant progress toward reverting the world to normal she confronted him unsuccessfully. There, Ritz's hair was naturally red, giving Ritz a significant vested interest in the preservation of Ivalice, which she realized was based on the video game Final Fantasy. Ritz was one of the people accidentally whisked away to the illusory Ivalice by Mewt using the Gran Grimore. Provided a person met certain standards, she could also make fast friendships, such as that which she had with Marche Radiuju. While certainly difficult to deal with, Ritz did have a strong sense of morality and always stood up for the underlings around the schoolyard, particularly Mewt Randell. This pressured reinvention covered more than just hair Ritz adopted a bossy, argumentative, highly self-righteous alter-ego around the schoolyard, ensuring that all her classmates knew that she was not a girl with which to be messed.
This left her mother no end of grief, as she simply wanted to see her daughter be herself and not what social pressures dictated. Albinic from birth, she was accepted by her peers in early childhood but rejected by them at school-age, beginning her habit of dying it red.