how relevant is C today?

[Sandra-24]

C/C++ is used for a lot of things and not going anywhere.

I recommend you learn it not because you should create applications in
C or C++, but because it will increase your skills and value as a
programmer. I recommend you even spend a few weeks with an assembly
language, for the same reason.

However, when it comes to beginning new things with an eye for getting
the job done, C/C++ (or Java for that matter...) is usually a bad idea.
That having been said, there are always exceptions to the rule and
you'll learn better how to call things as you advance your skills as a
programmer.

There are also sometimes parts of your application that just cannot be
optimized any more in a high level language, and might benefit from
being converted to C or C++. But do yourself a favor and only do such
things after taking careful measurements and exhausting other options.
Many time consuming algorithms don't gain a noticable speed improvement
in lower level languages.

-Sandra