Computer engineering (at least where I studied) focused at the boundary between hardware and software: how electricity flows though computer circuits and chips, what that implies for power usage, and what software would run on the chips and what software would interact with those circuits.
So I would suggest you focus on math (trigonometry of course, and calculus if you can get it) and physics -- specifically electricity and magnetism, circuits, and all of that. If your high school offers computer classes (programming, computer networks), of course take those.
If you are wanting to focus on game design, the math is still useful for understanding some of the advanced programming techniques, and the physics classes should be focused on Newtonian mechanics (when a player jumps, what equation describes the path they fall, and how do we tweak that behavior so that it's fun? -- after all we can't double-jump in real life.)