How do i calculate the dates before the year of 1900 ?

when i enter a year (Example) 23/08/1875 to 14/09/1895 i get an answer that says #Value im using this to find out the age of someone up to todays date - formula

=DATEDIF(B11,NOW(),"y") (B11 been the cell ref)

in B11 is 23/08/1875 the answer should be 140

can anyone help please

home database.xlsx