Secondly, having looked at the 1851 census, I see John Corkill & Margaret & family were at Ballajorey, Maughold.
I checked this farm in the 1841 census, and found:
2 1 2 Ballajorey
Margaret KERMODE 55 Independent Isle of Man
Edward KERMODE 15 Baker Apprentice Isle of Man
Elinor KERMODE 15 Dressmaker Isle of Man
Margaret KERMODE 20 Isle of Man

- So this is another possibility to be your Margaret, although her age is not as close to your Margaret's ages in censuses (when not rounded) as the previous bapt given.

[Older children of this couple not included.]
Margaret [daur of] John Kermod/ Margaret Moore [bapt] Parish Church 8 Nov 1818
Jane John Kermod/ Margaret Moore Parish Church 11 Feb 1821
Elinor John Kermod/ Margaret Moore Parish Church 28 Dec 1823
Edward John Kermod/ Margaret Moore Parish Church 14 May 1826

Sue