You really need to start with the state/county/city health department. Not sure how this is done in Indiana. Most states make it nearly impossible to run a legit home based catering kitchen. It is possible to do this on a part time legit basis, but it generally involves getting lucky enough to find access to a commercial kitchen. I got my start much the same way you did and worked into local farmers' markets using a shared kitchen. I made a spectacular find on eBay last winter and now have a commercial kitchen on wheels. Works great for festivals or catering.
Bottom line is the HD will drive a lot of your decisions getting started. Best of luck!
Brian Sweeney - CBJ #3691 - '77 Step Van Mobile Kitchen, Horizon Marshall, WSM with Pro Q Stacker, Weber Kettle & Smokey Joe GOLD.
"Any sufficiently advanced technology is indistinguishable from magic" - Clarke's Third Law