You can do a lot without knowing a lot going with unreal(game engine), mixamo(character animations), and whatever free models you can find. Unreal has some starter projects, a small 3D arena with a default character already controllable and animated, you can ease into it learning how to replace whats already there and then add on new things.
would be nice with a test for a sealed fan like I described. the problem with that setup is that the negative pressure will try to pull from both windows, competing with the fan trying to blow out and not getting as much flow
air will be blown over your body either way, all you're changing is the direction the air is coming from. blowing from the ceiling means blowing hotter risen air