Had a quick look on other censuses and there doesn't seem to be any Emma Smarts born Pimlico 1854 +/- 2 years. There are a few choices for Emma Smarts born Middlesex c1854, so best bet is probably to get the marriage certificate to make sure you get the right Emma -
eg; 1861 census
Emma b. c1852 St Georges East, dau of John and Emma, living in Bethnal Green
Emma b. c1852 St George Hanover Square, dau of George and Harriet, living in St George Hanover Square
Emma b. c1854 London Middlesex, dau of William and Maria, living in Westminster St Martin in the Fields
Emma L Smart b. c1855 St Luke Middlesex, dau of Thomas L and Louisa S, living in St Lukes Middlesex
Theres also one or two more possible Emmas in 1871 census.....
