[@PlatinumSkink]

Erika has only lived a relatively short 15 years and hasn't really done much. It was important to establish the mother because she is relevant down the line, moreso than Erika's childhood. Plus, since it was important to establish the reason why Erika would be given a spot in Kalmia's thing.

Yes but "in her youth" and "after Erika's seventh birthday" are massive leaps in time, too. The point to establish from that is that Erika's mother is good. Very good at battling, but it was something that took a significant portion of her life to achieve.