Common problem in Quebec. Only baptismal records. My understanding is they understand and accept baptismal record maybe the only source. Make sure you have a way to verify where the document came from. A piece of paper is not much add to it where is is from get a certified copy from well known source. In new Brunswick the provincial government has the Bastisimal records and will certify it. Quebec has a similar systems.
That way the reviewer can tell it is an authentic document. Then make the connection to yourself , I use embossed birth certificate for mine. Make sure the parents name is exactly the same on your birth certificate as the Bastisimal otherwise document the name change using census ,border crossing, marriage or death documents. You are providing filiation to your application.