If you're new to growing your own food, I indeed highly recommend you
initially stick to food from shops as you start learning to grow your own, transitioning gradually as your skills improve and can rely more on yourself. If you completely & abruptly stop buying food, relying entirely on your own farming, with no transition period, trust me you'll starve.
Likewise, stick to schools initially until you are sure you've got a solid grasp of core concepts, as taught & validated by people who know what you don't but should, then start transitioning away as your education can stand on its own. I've known too many "self taught" people who, while yes they can function in industry, suffer gaping glaring holes where early formal thoroughness would have closed them.
