But I'm open to any advice.
I went BASIC -> C++ -> Java -> Python (some years ago) while learning programming. Learning memory management fundamentals in an unmanaged language felt enormously helpful in recognizing the bigger picture in later managed languages.
... But! It wasn't required.
Advice: Know what language(s) your target job market (there's a lot of programming) uses, and spend more time / practice on those. Most hiring folks don't know enough to evaluate language knowledge from a theoretically similar perspective.
Now if you're in to mastering complexity, C++ can be a great choice, as there are a ton of complex things to learn, but I would take a look at job postings where you think you might want to end up to see if it is actually required. It is very unsexy to talk about on HN, but for pure employability, Java (and other JVM-based languages) are probably the best in most areas. There are tons of remote jobs, and pretty much in any city, plus you can branch out into other JVM-based languages (e.g. Scala!) once you feel so inclined and still incorporate that at work. C# and F# have a similar "progression" and are now completely open source too!
Good luck, whether or not you end up choosing C++!
So I would explore and see how far you can get in math before investing to heavily into a specific language. If you want to learn one that’s useful in many domains and is easy to learn while focusing your studies on math my suggestion is Python.