Assuming you're an American, it's helpful to consider the concept of "Americana." I get into a bit here in another question about the history of the pledge in American schools:

Americana can best be thought of as the packaging of American history and touchstones for the next generation. It's a framework that led to the "Washington and the cherry tree" genre of stories, generations of school children memorizing the preamble to the Constitution, learning Christopher Columbus "discovered" American and mass dislocation and genocide of Indigenous people was simply "manifest destiny", and other broad strokes about what happened on this soil. This simplistic approach to American history was embedded in the texts children read and the way teachers talked about history. ... This meant that the 400th anniversary [of his landing] was everything. Schools across the country were planning celebrations, not because they coordinated, but because celebrations of events related to Americana was something you did in American schools.

I also give a bit more context in this response on Columbus himself and on how/why American schools teach "bad" history.

To summarize the gist of the other texts, American schools deliberately teach a simplified narrative around American history in part because the mostly White teaching force is uncomfortable with and hasn't been trained in how to teach more complicated history and because the simplified narrative is tightly linked to a skewed sense of what it means to be American. Columbus is basically seen as the first of the "Great Men" who made America and serves as an avatar for the "American" spirit of discovery and exploration. The good news - without getting to far into modern politics - is there have been concentrated efforts in recent decades to prepare teachers to teach more complicated history and to re-situate Columbus in history, even for the youngest learners.