As others have mentioned, start off small, and work your way up. Use tutorials/C++ books to learn the very basics before tackling any real projects.
Instead attempting to make your own games when you've just started learning C++, try modding existing games/engines for starters. It always helps to have something that's already working in front of you, where you can mess around, make small changes and immediately see results on-screen. I remember one of the first bits of C++ I wrote was in the HL1 game code, where I wrapped the bit that spawned gibs when a scientist was killed in a for loop, increasing the gore by 10x. Seeing how big of a visual change two additional lines of code made got me hooked immediately.
That being said, I wouldn't suggest GoldSource as a starting point - a lot of that codebase is very much out-of-date (some of it is like 20 yrs old at this point). Try the Unreal Engine, their codebase is fantastic, and there's loads of documentation/demos available, where you can play around stuff that already works.
Finally, if C++ is the first programming language you're attempting to learn, I would also consider starting off with a simpler variant in order to grasp the very basics. C# is a far more easy-to-use (and in some cases more powerful) variant of the language, that would help you wrap your head around C-based language basics without having to consider the low-level memory management that you'd inadvertently run into when using C++. Unity is a great game engine that runs on that language, very much beginner friendly, loads of documentation, etc.
A lot of programmers/game developers here (myself included) have gone through the initial urge to create something huge as their first project (own rendering engine, game, etc.), and have fallen flat on our faces tons of times. Your initial goal should be finding a way to learn the basics without getting discouraged, setting small goals to keep yourself interested/motivated to keep going. Plan for the long haul and you'll get there.