I'm taking a babysitting course and I'm just wondering but I know I have to be 11 to take the course... Any awnsers :)

You can babysit at any age. There's no Canadian law on this subject.

There MAY be local laws - but nothing the covers the whole of Canada.

It is not a law on this, there may be some local codes, Normally it will be your maturity, permission of your parents and finding a family that will allow you to watch their children.
As customs go, locally here in Atlanta GA, most are 12 when they start but there is nothing to stop them from doing it eariler.