I've been making Machinima films using game engines for the past 20 years or so, including working with people like EA, the BBC, et al.

(I'm actually the guy who coined the word "Machinima", with a colleague, because we needed a better way to describe what we did than "Quake Movie".)

So I had a lot of game engine experience before I jumped in.

As for beginners getting started: Unity, Unity, Unity. Grab Unity and start learning - you can get a simple VR experience going in a fairly minimal timeframe.