This looks like the family in 1851, and Dorothy born in 1846 which agrees with her age in 1881 and the area is right for Pittington.
HO107; Piece: 2393; Folio: 157; Page: 24 Newbottle
Thomas Young 43
Dorothy Young 38
Dinah Young 17
Benjamin Young 13
Mary A Young 9
Margaret Young 7
Dorothy Young 5 Houghton,
Thomas Young 3
Her ages in 1871 and 1891 don't agree however.
Stan