I would suggest working at one first, to see if you like it, before you would consider being an owner of one. There will be a bunch of regulatory hoops you have to jump through, including accreditation (proving that you have the capability to properly care for the kids), and these will vary based on the location of the day care.
You will need to start thinking about the following:
-Space: where will you operate the day care? What legal hurdles are there? Insurance, zoning etc.
-Staff: who will you hire? how will you pay them? what benefits will you provide? do they need to be accredited?
-Legal: what legal protection and procedures do you need to follow
-Customers: where will you source customers? what age kids will you take care of? Will you need separate age groups of kids or can they all play together?