A girl who wrote a novel at age 9. The interesting bit is this, the publishers published her work without editing her spellings, grammar and punctuation.
Here's an excerpt from Wikipedia:
"Daisy Ashford, full name Margaret Mary Julia Ashford (later Devlin) (7 April 1881 – 15 January 1972) was an English writer who is most famous for writing The Young Visiters, a novella concerning the upper class
society of late 19th century England, when she was just nine years old.
The novella was published in 1919, preserving her juvenile spelling and
punctuation. She wrote the title as "Viseters" in her manuscript, but
it was published as "Visiters"."
Source: Daisy Ashford