Hi
Found this in the 1911 Irish census at the address Glen East -Cape Clear
Curtin Edward 45 Male farmer and fisherman born 1866
Curtin Catherine 40 Female born 1871
Curtin Denis age 21 Male -fisherman
Curtin Mary age 19 Female
Curtin Patrick age 17 Male
Curtin Catherine age 16 Female
Curtin Nora age 13 Female
Curtin John age 10 Male
Curtin William age 9 Male
Curtin Michael age 7 Male
Curtin Florence age 6 Male
Curtin Edward age 4 Male
Curtin Jeremiah age 3 Male
Curtin Garret age 0 Male 2 months old
Census was taken in April 1911
15 children born in total, but 13 survived
Catherine and Edward married in 1889, you were right
Looks like you found your relatives
Below all the Curtins of Cape Clear in 1911:
Curtin Denis Ballyieragh North Cape Clear Cork 50 M , living with the Coughlan family as a servant, unmarried
Curtin Ellen Ballyieragh North Cape Clear Cork 45 F , domestic servant, single living alone
Curtin Johanna Ballyieragh North Cape Clear Cork 80 F , living alone (widow)