Jean Crow ALLAN , 18581939 (aged 81 years)

Name
Jean Crow /ALLAN/
Given names
Jean Crow
Surname
ALLAN
Name
Jean Crow /McDOUGALL/
Type
married name
Given names
Jean Crow
Surname
McDOUGALL
Birth

The headstone for Jean is inscribed that she was born in 1850 yet her birth registration was not made until 1858. Can anyone help with the correct date please?