NanMcCarthy on Family Tree Circles

We have her name as Mary Margaret McCarthy born 1918. Married Ernie Rupert Ladbrook (1901-1969) in St Pancras, London in 1939 when she was 21. No parents names entered on marriage certificate. Had 3 children 1938 through to 1941. Children born London, Colchester and Northampton. Died in Northamptonshire in 1941. Unable to find any information on where she was born or where she came from.