So what to do with the mother? The heroine has to leave and set out into the world, and grow up. I was vaguely thinking of making her rather old, so that she could die of old age while the heroine is still rather young, but it would rather color her setting out on her adventures.
But having her just keeping the home fires burning didn't fit the story either. . . .
Began to think of her being an adventurer, who had leave the Gamelit adventures for some reason -- perhaps a curse? -- for a long time. Perhaps she acquired the heroine and stayed longer than originally intended -- but then, the heroine has to fare forth alone. The thing would have to keep her for long than it took to launch the heroine, even though she sets out rather young.
AND -- if she's an adventurer, she will have to have a character class. Which would tell us much of how she instructed the heroine as she grew. If a cleric or even paladin, religious knowledge would be deep; druid or ranger, likewise but a different concentration (and also one that makes the heroine less of a fish out of water); sorcerer would match the heroine and have its advantage; fighter or rogue would leave the heroine hanging for more which means she needs to scramble to catch up -- always interesting, plot wise. And how old can she be?
And if her departure is not permanent -- see comment above about homefires -- I still have to keep her mostly out of the heroine's way.
(Meanwhile, the nature of the curse is going to create problems for the heroine if I spin it right.)