If you have any food service business, you should probably have standard liability insurance - i.e., so if someone gets hurt on your property or eating your food, you have some coverage. An insurance agent who specializes in restaurants/bakeries could give you more specific advice.
As far as teaching classes vs. baking cookies as a business (if that's what you're asking), they're very different businesses, in my opinion, requiring different skills and know-how. I'd say this to anyone starting out: I'd focus on establishing skills and a distinct style as a cookie decorator before trying to get into the business of teaching those skills. A deep portfolio of well executed cookies is pretty important to have in order to sell classes. Of course, knowing how to price to make money is also key. Teaching classes is not easy and takes tons of prep and cleanup. Setting price, as in selling decorated cookies, involves having a clear understanding of your cost structure.