[OMFG!You'reActuallySmart!]

There is a huge demand for graphic design, anything from photography as you mentioned, to video games, cartoons, advertisements, websites, etc... . Starting a business fresh out of college would be difficult since you need some background knowledge in business and accounting. It's definitely something foreseeable in the future if you end up liking graphic design and form partnerships with other individuals or companies. I'd say to work for a company, although keep in mind, you're not going to be spoon-fed, except at first depending on the company, so there will be a fair amount of independence on your part as well as collaborating with clients and fellow graphic designers. I'm not sure how long you should wait as it depends on whether you can find willing partners to be part of your business. Perhaps there will be a few from college, but you're going to need knowledge of business and accounting, not to mention marketing to get yourself known.