It is quite a misfortune to be born the eldest of three.
To be an only child is to be your parents' only chance. To be the youngest child is to have all of your elders' possessions trickle down to you. Even to be a middle child means you will have allies above and below.
The eldest is... not a sacrifice. Nothing so crude. But her fate is a necessary evil.
Sophie Hara is the eldest of three sisters. Her parents are well-off independents. Her mother died when she was two years old and her sister Lettie was one, and her father married a younger woman, Fanny, who shortly gave birth to a third sister, Martha. Her father schooled them all very thoroughly. Sophie was the most studious, even though she was doomed. She had enough of a head for languages to learn, in addition to English and Japanese, all of Latin, Welsh, French and another of her choice. She chose Gaeilge, because she found Eire quite unaccountably romantic.
In addition to her schooling, she frequently had to manage her younger sisters. "It's not fair!" Lettie would shout at Martha. "Why should you have all the luck being born last? I'm going to join an enclave and leave you to rot!" To which Martha would respond that she would graduate without having to suck up to anybody, so there. Then Sophie would drag them apart and mend their clothes.
She was very deft with a needle. Sadly, it did not stop at deft; it turned out to be her affinity, clothes and clothes alone. Especially hats. She could work a forge if she had to, but a needle in her hand could sing. This was not good. Everyone needed clothes, and it was a good thing she could make them so well, but they needed weapons more. Good weapons, not passable weapons.
This is one of the innumerable reasons that Sophie Hara is resigned to her fate.
Her fate is to survive long enough. Long enough to pass things down. If she dies in her freshman year, her room will be picked clean by scavengers long before Lettie gets there. If she survives to sophomore year, she will be able to give Lettie hand-downs, enough to keep her going without depriving Martha, and let her clean out her room if she does die. If she survives to junior year, she can give Martha the rest of her hand-downs, and die satisfied.
Lettie and Martha do not like this plan. Lettie screamed at her and burst into tears, when she told her, and Martha had a face like granite the whole time. But she told them, it's for you. It's always been for you. I don't have anything I want after except you two to live and be happy.
As she stands there, stomach gnawing at her, head shaved and hair coiled into a rope at the bottom of her full bag, and feels the nauseating pull of the Scholomance, she almost smiles.