I have two pieces of advice. First, expand your horizons. Yes, Windows jumping games using a game creator are a
great start, but there is so much more. At 12, when I started off, I was writing very similar games, albeit using Python and Pygame rather than JS. Your route is equally valid, with its own unique challenges, and hey, in the end you get the same result. However, from here, the paths begin to branch. While the Windows world you've embraced will lead you to Visual Basic and eventually Visual C++ and C#, you could take another path. At 11, I installed Ubuntu Linux for the first time; at 14, I switched to Arch. This was probably a bad decision, given I knew nothing about the OS and had to essentially re-learn everything. You might be intimidated. Don't be. Learning your way around Unix now will make a world of difference later. By 16, I had written my first compiler, a basic baremetal assembly kernel, and an interpreted language with a decent optimizing compiler and VM. I am still not an amazing programmer, and I still have a lot to learn. Don't doubt yourself because of your age. My second piece of advice ties into the first: don't try to use your age to gain an advantage. Not because it's unfair: because it will bring you more personal validation when people praise you because of the quality of your work rather than how young you are. It's the diffence between making a good program, and making a good program
for a teenager. Also, it makes it far easier to find jobs.
Source: My own experiences as the 16-year old (breaking my own rule here for the first time) author of the solid programming language.
P.S. I'm not trying to be arrogant. I just don't want you to repeat my mistakes. Don't be afraid to do things that seem difficult: with research and a little elbow grease, you can accomplish anything, and nothing anyone says can take that away from you.