Can a 55-year-old Canadian become a citizen directly?

You can't. A series of conditions need to be met:

1, a permanent resident of Canada;

2. Have lived in Canada for four of the past six years;

3. Apply to the Immigration Department;

4. Take the naturalization test and English (or French) test and obtain qualified results;

5. Obtain naturalization approval and take an oath of naturalization.

Originally, it was stipulated that naturalization applicants aged 55 and above could be exempted from English test, but now the New Deal has raised the age of English test exemption to 65 and above.