Don't make your own 3D Game Engine - anyway, here's how I made mine. 

Now you're thinking, but the real question is "when killed JFK"?

Teach me

I love Godot! Initially I did a prototype using Godot - it worked well enough, but I had a very tile-map based idea and found that I was asking Godot to transform data and geometry in ways that would work better threaded directly into the engine. It probably would have worked well in Godot, some things would be harder, some easier, but once I got the prototype working on my own engine, it felt like I had the momentum to keep building. I had no idea just how far I still had to go. Time again I'd probably still go custom.

people say that because most folks who want to make a game are amateur programmers, and working with C/C++ and OpenGL etc is very daunting for people who don't have coding experience. that said, if you can code then I really think doing it "from scratch" like this is better, as you'll know and understand every part of your game much better when it comes to things like optimizations down the road. plus, for large behemoth engines like Unreal, getting used to their APIs is such a daunting task on its own, you might as well spend that time learning how to do it yourself IMO it only really makes sense if you're either A) cranking out template games or B) really REALLY need something that it does for specifically, most notably I'd say multiplayer - the builtin multiplayer capabilities of the major engines make that a lot quicker if you're worried about time to market

Bilbo baggins vibe by reading your comment