C++ is a language with a relatively high entry barrier (meaning it’s quite difficult to learn), but the reward is greater because it allows more direct control over the hardware and graphical processes (something very important in video game design).
It is an object-oriented language, meaning it uses internal structures to better organize code into reusable blocks (classes and objects).
It is by far the most commonly used language for writing game engines, and some engines (such as Unreal) only accept information written in C++.
There have been a lot of suggestions here, and they are all viable, so here is so something to help you choose: python is the easiest, but the least controlling to use, while java is slightly harder, but gives better control, and then there is C#, which is harder still, but gives very good control, and finally C++, which is the hardest, but also the best for control. Taking this into account, and the fact it is used quite often for its rank in this list, I would recommend C#, however feel free to use whatever u wish from these.
(P.s. heard of Fortnite? Big hit! Uses unreal engine, which is coded in C++, which makes that another good option, I would pick one of those two, C++ or C#)
personal I think python is a good one, easier to learn and only growing in the industry. Modules for c to python development already exist so they fot together, so after you get python, try a bit of c, most of it will just feel natural.