There are areas of our ignorance we are aware of, but there are also vast spaces of our ignorance we are unaware of. This area is perhaps where we would exhibit the Dunning–Kruger effect. It is really important for us to know and understand our circle of competence, and to create boundaries and rules for ourselves to navigate within, and beyond this circle.
Think of it as comparing a person who lives in a town for many years and know his way around it by his senses and strong local knowledge, against an out-of-towner who had got hold of a map and managed to navigate successfully to a few places of interest. The guy who is new in town tend to overestimate his understanding of the place and might make overly risky decisions or commitments as a result (eg. showing friends around, or bragging loudly about his knowledge of the best local foods).
One of the critical skills that we need to acquire especially as we are new to a space, and trying to grow ourselves, is to be able to develop not only the self-awareness but the toolkit to navigate a new space when one runs the risk of getting into the Dunning-Kruger effect. In fact, even as kids, we should already be conscious about what is happening and how we can deal with such struggles.