Wow, that's a tough question. I don't remember much about being 10, and making games is pretty hard!
I don't have any short answers, but I do have two longer answers:
1) Try asking about this at your school, or look for other schools nearby or summer programs that offer classes on making games. Your parents or teachers might be able to help you find these. All the game-making tools that I've used expect you to know things like geometry, algebra, and basic programming concepts, which I think most schools don't teach until you're older. Sometimes colleges & community centers offer game-making classes that are open to the public, too, though they may be too short to get into much detail.
If you're in the US, it looks like https://code.org/learn/local might help to find local classes. I haven't used it, though.
2) If you want to try all by yourself (which can be very hard), a lot of people recommend starting at http://www.sortingh.at/. It helps to pick a tool to start with (like "Haxel," or "Löve," or "Phaser"), then you can watch tutorials on Youtube, or look for Coursera classes, or try other ways to learn how to use that tool to make games. (I used Unity, but it's overkill for such a simple project like this, and there's a lot of other concepts that you have to learn to use it. I would not recommend Unity for your first game, unless you already know a lot about programming and 3D graphics.)
Some of my coworkers taught themselves how to program at your age just by reading documentation and spending a lot of time trying, but I don't think I would have been able to do it.
Also, it's probably going to be more helpful to ask teachers/parents rather than to leave comments on itch.io. A lot of us have busy lives and don't really watch for comments, so you probably won't get many answers here.
Anyway, whatever you try, good luck to you!