Also, the manga previously stated her age to be 11 during chapter 6, chapter 8, and chapter 11, which would put her at 12 years old on 1924-11-15 after she announced her birthday on the September 24th 1924 Dacian invasion in chapter 12, which subsequently should date her birthday as September 24th 1912. On a wiki page, Tanya's registered birthday is listed as September 24th 1914, which I used in calculating her age in the post below. I'm not sure if that's the webnovel's official birth date and if the manga is supposed to have a different age, but I take it as more evidence that someone's messing up dates. Conclusively, someone is fucking up dates on this manga often enough that it bothers me to the point that I have to keep track of everything.