She said to me she has not renewed her citizenship
But I cannot understand what does it means
There is no such thing as "renewing" citizenship. You are either a citizen, or you aren't. You don't lose it by not living in the country.
What is important for you, is if your
parent is a citizen or not and where they were born / how they acquired citizenship. Were they born in Canada? Were they naturalized as Canadian citizens?
If your parent was born outside of Canada, then most likely you are
not a citizen. If your parent was born in Canada, then you would be a citizen.