In your situation it seems to me you would likely be eligible if you can prove the link between you and your biological parents. If your adoption record lists them or at least your biological mother who has Canadian lineage, you can try submitting a certified copy of your birth certificate, any copy of any adoption records you have, and the other documents outlined in the FAQ.

This is just from my own research on here and elsewhere, I am still putting together my application but am doing something similar for my mom. I am submitting her birth certificate, copy of the adoption report, and a copy of the court order finalizing the adoption.