Her Hogwarts letter changed many things for her. The accidents suddenly made sense. They had an explanation for all the oddities, but the invitation to a magical boarding school raised many new questions and decisions. Suddenly, she was not necessarily on the Oxford-or-Cambridge track that William and Charlotte Granger had always planned for their own and only daughter. That was what they had always wanted for her and what she thought she had wanted for herself. But she had a new option; a completely new world was opening to her. She thought she needed to explore that to understand the part of herself that had never really fit in at school.
Her parents had let her go, but part of her always worried that she had disappointed them. Suddenly they couldn't brag to her friends about her accomplishments at school. They couldn't even understand most of what she wrote to them about her classes. Some of that may have been because she sanitized things for their protection. She did not want them to realize how dangerous her new world really was. She did not want them to know she could have been killed by a mountain troll or a Basilisk or even the occasional exploding cauldron.
As she got older, school and living in the Magical World only became more dangerous. She faced hundreds of Dementors and was saved only by the exceptional spell-work of her time traveling best friend. Fourth year, Harry's life was threatened more than her own by dragons, various lake beasts, a labyrinth full of danger, and finally Voldemort himself. But then, she could have drowned during the second task and there was always the possibility of one of the other monsters being poorly contained. Fifth year the main threat was from Delores Umbridge, ministry toady, until their end of the year misadventure at the Department of Mysteries. There she suffered an injury she could not completely hide from her parents. Still, she brushed it off as the result of an in-class accident. Sixth year saw her and her friends fighting off a squadron of Death Eaters, thankfully assisted by members of the Order of the Phoenix.
Still, for all of her lies, omissions, and half-truths, she did not really feel that she betrayed her parents fully until after Dumbledore's funeral at the end of sixth year. She and Ron had promised Harry that they would help him find and destroy Voldemort's remaining Horcruxes (even though they had no idea how to do that). Fearing that her parents would become targets for their hateful foes, she wiped herself from their memories, gave them new identities, and sent them to Australia. She only hoped she would be able to undo her sins against them and beg for their forgiveness.