Could you give us some idea as to when the children of your Mary were born, the eldest would be most useful

There appears to be a Mary Ann Churnside baptised on15 July 1814 at Tynemouth, Northumberland.
Parents are given as William whose occupation is mariner and Mary Ann. Residence at the time was Stephenson Street.
I think she may have married William Forster in March 1832.
I can't see them on census though to confirm. Found in 1851 see next post
FORSTER, WILLIAM CHURNSIDE mmn CHURNSIDE
GRO Reference: 1838 Sept Quarter in TYNEMOUTH UNION Volume 25 Page 365
FORSTER, ALEXANDER SHARP mmn CHURNSIDE
GRO Reference: 1840 Sept Quarter in TYNEMOUTH UNION Volume 25 Page 409
BAPTISED 6 Sep 1840 - parents William & Mary Ann FORSTER, RICHARD mmn CHURNSIDE
GRO Reference: 1845 Dec Quarter in TYNEMOUTH UNION Volume 25 Page 422