I cannot stress this enough: Develop a strong sense of Problem Solving. Not to mention, as a Game Designer your most important skill is the abillity to Listen. If you can do both, you will be able to tackle all sorts of adversities. If you're especially interested in Design, I highly reccommend reading The Art of Game Design by Jesse Schell. That book is golden, though I haven't finished it yet myself. Whenever you play games, think about the experiences they create, and why those experiences are / are not enjoyable, and how the rough areas could be improved. Prior to college, working hard at foundational Math skills would definitely give you a leg up on other students, I know that my aptitude with Math was definitely invaluable in some of my Computer Science classes, especially game programming. Lots of vectors and physics and stuff that others struggled with came pretty easily to me due to my strong math background. I definitely think getting a degree in something that you can still use even if you can't make it into the Industry right away is a wise decision. Computer Science is very applicable for this reason. I sorta think that if you're going to school to learn Game Design, unless if you're getting that education from Digipen or equivilant, you're sorta doing it wrong, as a lot of that stuff you can learn just by making Games on your own time. Don't worry about programming languages yet, just choose a major language and learn it. The fun thing about Programming Languages is that they mostly have the same basic elements that you'll be using time and time again in your programs. An If Statement in Java isn't that different from an If Statement in C++ which isn't that much different from an If Statement in Python. Once you learn the basics, swapping between languages just takes some basic adjustments in syntax and perhaps a few higher level ideas, and then you're set to go.

Most triple-A games are written in C++. The PlayStation Suite uses C#. Minecraft was written in Java. Roller Coaster Tycoon was written in Assembly. (More fun fact than practical comparison) If you need to prioritize, pick a programming language to focus on over HTML and CSS (Unless you're determined you want to try and make HTML5 games). Popular starting choices for programming include Java, Python, and C++. One of the best things you can do right now is to pick a language and learn it like the back of your hand. Then learn another, and another.