Have a problem with an Emily (Murrain), a daughter of William Henry Murrain & wife Mary M.

Emily first appears in the 1891 Census, living with her parents, aged 2, born Kelly.
She appears in 1901, again with parents, aged 12, born Kelly
She is in the 1911 Census,with parents, aged 22 but with slight difference this time being said to be born at Lifton.
In 1918 she appears to have married Charles E. Alford.
There are 2 possibilities in 1939, one being as a widow and housekeeper with Sidney Trickey & family at Tiverton, said to be born 26 May 1889, and the other at Tavistock with Charles Philip Edward Alford said to be born 23 August 1888 - my guess would be the latter.
However, whether 1888 or 1889, I have failed to find any evidence in birth records, for registration of the birth of Emily.
Would anyone have any ideas which I have missed??
David