Reposting this seeing as the forum ate my post last time.
Combining wood and steel framing is unusual, and it's not unrealistic for wood joists to span that length.
This window frame looks like it belongs in a bunker or an explosives testing facility, purely because of the texture on the inside of the window frame. I'd make the whole frame that generic grey metal texture. As an aside, glass doesn't have to be placed in the direct center of the frame. While this window is a lot more detailed than you should ever really make it in a map, it should give you an idea of how the glass is attached closer to the outside of the house than the inside.