Jane's age varies somewhat, but I don't think that this is too unusual! This age equates with the 1881 but not the 1871 census.
I have found a baptism for her: Jane Murdock baptised 14 January 1838, born 4 December 1837 to Thomas and Jane Murdock at St. John, Horselydown Parish Church, Southwark. Her father Thomas was a 'slater'
Anna