Is it worth learning C++ at my age, or should I stick with JavaScript/React?

Im 16 and entering my junior year of high school. I’ve been learning JavaScript/React and have made a few small projects, but lately I’ve been losing motivation with it. Recently Ive been getting the urge to learn C++ partly because I’ve become really interested in game development as one of my career options.

The main thing I’m unsure about is whether I should actually switch. I’ve heard that it’s better to commit to one language and get really good at it first, since learning one language well makes learning others easier. I don’t want to fall into the habit of constantly jumping between languages without getting good at any of them.
At the same time, C++ seems like something I’d enjoy learning, and game development is something I’d like to explore.

If I do start learning C++, would it be better to do a short crash course to learn the basics and then jump straight into projects, or should I follow something like LearnCpp.com?

I’d appreciate any advice!