Yeah, that's pretty much how it works. Theoretically speaking, understanding something is the whole point of knowledge. In this case, if you understand mathematics, then you don't have a problem with understanding mathematics. Is that really all there is to this opinion page? I'm not sure if you were trying to go anywhere with this or you just wanted to sound really deep about math.
What makes a subject or topic difficult? It is just that we do not understand it. We may not see or perceive the beauty of something because our way of introduction was not clear enough. If that veil is gone, a new vision / picture emerges. An advice: do not rely too much on textbooks ...... .