Part of the difference in your case is the motivation for learning. Many of us in grade school had a motivation to get good grades/pass a class outside of the pursuit of knowledge. Even for those of us that really liked to learn, it was usually directed at a certain subject matter and not everything that we would need to be successful as adults (I loved math, but would never willingly write an essay if I could get away with it). Because grade school kids are "forced" to learn things they do not want to, they always look for the easiest way to get through the material, and AI provides a way to do this.