You don't need a license to get a business #. Currently you can have up to 5 dc kids plus your own if you have an unlicensed daycare. If you work for a licensed agency you can only have 5 kids, including your own (they will not count in the numbers if they are over 6yo)

I joined an agency during my first year and then I went unlicensed. I don't recommend joining an agency, since there is nothing you can't do by yourself and they take a big percentage of your income.