Hi Debbie and Elaine
This is the 1901 census entry for the Catherine in Glenbervie - all the children showing as born in Glenbervie:
William Petrie 53, gamekeeper, b. Durris, Kincardine
Elspeth Petrie 50, b. Nether Banchory, Kincardine
John Petrie 12, son
Douglas Petrie 10, son
Joseph Petrie 8, son
Elsie Petrie 3, granddaughter
Christina McKenzie 24, daughter, b. Glenbervie
Catherine McKenzie 6 months, granddaughter, b. Glenbervie
Address: Ladiesleys, Glenbervie
Monica

Added: Catherine's age of 6 months would fit for a 30 Sept 1900 birth. Her birth cert. would show details of her parents, including mother's maiden name. It will also show parents' marriage date and place. It would also be worthwhile trying to get, if you haven't already a copy of her marriage cert. in England (?) which will include at least her father's name to let you verify the right family for her.