Birth year is 1859 per 1911 Census.
Perhaps the 1875 marriage age of 20 was overstated?
In 1881 Tom Exton is with his parents.
1. Which puts the duty on Annie Exton to fill out the Census Householder Form declaration in 1881.
1881 Boston, 1 Corpus Christie Lane.
Annie Exton, Wife, 23, Tailor's Wife, Gosberton Lincoln.
Annie Exton, Daur, 5, Scholar, Boston.
William R. Exton, Son, 4, born Boston.
Tom Exton, Son, 3, born Boston.
Rose Exton, Son, 1, born Boston.
Rose Exton still at home in 1901 aged 21.
1891 St Martins Hill, Lincoln
Tom Exton, 41, Tailor, born Stamford
Annie Exton, Wife, Marr, 32, Nottinghamshire, Gosberton.
Annie has at least 3 Census declarations of Birth 1858-1859.
2. 1891 Born Nottinghamshire, Gosberton?
I wonder if the Exton's did write that on their Householder declaration that Annie Exton was born Nottinghamshire Gosberton?
A geographical check of Nottinghamshire indicates a place called Osberton Hall on the Osberton Estate.
Any Estate Worker, or Gentry mentioned in family folklore or notes?
3. Have you found Annie in the Census image as Annie Moore, a Single woman, yet?
Mark