The day that she received her Hogwarts letter Minerva was ecstatic; finally, she would be able to be a part of the world she'd spent so long hiding from others. It would no longer be her responsibility to hide her brothers' magic; instead she would be allowed to practise her own magic in a place where it was encouraged. She could meet other people like her and be herself after such a long time spent having to hide amongst muggles. At Hogwarts she would truly be able to excel, and she could finally be a part of the world that her mother had left behind.
Her mother watched her from the doorway, a strained smile on her face. She was proud of her daughter, and she couldn't have been happier, yet there was some small part of her that was jealous, too. Minerva would get to go to a place where she was free to use her magic, where she didn't have to keep her wand locked up in a box at the back of the closet. Isobel wanted what was best for her daughter – and that was definitely Hogwarts – but a selfish part of her wanted to keep her daughter at home where she wouldn't get to have the life that Isobel had given up for her husband.
All they could do now was look ahead; neither was certain as to what the future held, but they both knew that they would be following different paths. They would both make mistakes – the both already had – but they wouldn't be making the same mistake twice. And so, maybe it was a good thing that Minerva's magical career would begin in the same place that Isobel's ended, but that wouldn't be something that they would find out until a much later date.