From a thread posted at Yo! Liverpool, to which you should refer for more discussion including the reply I post here:

Originally posted by H. Oakes View Post

1871 English Census
8 Victoria St., Liverpool, near Stanley (now a printing shop, I believe)
John Kelly 50, joiner
Mary Kelly 50
Mary Jane Kelly 18, General Servant
Margaret and Harriet Kaybeck, servants

Any info would be appreciated...

Yours Truly
If this woman was aged 18 in 1871 that would have made her 35 in late 1888, probably too old to have been the Mary Jane Kelly who lived in Miller's Court, Spitalfields, who by all accounts was in her mid-twenties at the time of her murder on November 9, 1888.