It's a good plot. Football (*ahem* soccer *ahem*) plus system is a good combination. Writing quality is good as well, no errors that will disrupt the reading experience.
But the story feels a bit rushed, like the author is trying to cram everything into one chapter. It is detailed yet very fast-paced. I don't get much breathing room with one action after another.
The plot device is forced as well. No mother in the world would take the words of her six-year-old child seriously, especially if it involves his future. I understand the plot won't go forward if it's not done this way but I just have a hard time accepting that.
World building is Earth so there's no flaw to point out. Character design is decent as well. Overall, this is a good novel, I'm looking forward to seeing what kind of developments the author would show later.