FYI, here is the Canadian Citizen Act of 1947. The requirements for naturalization are on page 71.
http://www.pier21.ca/research/immigration-history/canadian-citizenship-act-1947
She would have needed to live continuously in Canada for one year before making an application to be a citizen and for four of the previous six years before the date of the application.
So if she moved there in 1967 then she could not have obtained Canadian citizenship before his birth in 1970.
Thanks for those specifics. Good job!