Explain Canadian citizenship by descent please

My mom is obsessed with geneology and my family is heavily French Canadian. I have DNA evidence of my maternal line going back a long way. My mom has traced our geneology all the was back to the 1500s in France. My grandparents were of French Canadian descent and were tenth cousins (most Québécois are related because there were only but so many settlers lol). I can trace back my family being settlers of Quebec through both my maternal grandmother and maternal grandfather. My family lived in Canada for hundreds of years!

But what seems to be a problem is that my family left for America (on both sides) between 1860-1909. My understanding is that Canadian citizenship started in 1947. So does that mean we are SOL? Even though we have Canadian heritage we don’t technically have a tie to a Canadian citizenship, because they left before that became a thing.

Is there any chance that this could still be an avenue for us? My sister is marrying a Canadian this year so she’s going to get citizenship one way or another. But we would be so happy if we could all get citizenship quickly this way!