Do you need to read theory to be a communist? No, of course not. Being a communist is an honest, natural response to the brutality of capitalism and the feeling deep in your bones that there is a better way. What theory can do, is help you articulate things

You can learn that there's a long-established discourse for most of what you'd thought of as your deepest and most revolutionary ideas, which is useful

You can learn that people have tried to put these ideas in practice, and that the history of these efforts is complex and at the same time highly ideological

And of course you may learn something new, which is a good in itself