Sola Scriptura, Literal Translationalist, KJV Only oopsie

 John 14:2a In my Father's house there are many mansions.

This was a prime verse for memorization for us young evangelicals. I remember memorizing it, quoting it back to my teachers, and listening to lessons about how cool it is that Jesus is preparing us each our individual mansions in heaven!  Yes, we believed that Jesus was literally giving each and every one of us saved people our very own mansion in heaven.  

As a child I was perplexed by this, but didn't speak my questioning out loud because we HAD to believe the Bible literally (unless a pastor or authority declared it figurative, like the institution of the Eucharist as the literal body, blood, soul, and divinity of Christ).  First of all, I didn't want a huge mansion.  I sweet, little Cotswolds-style cottage with a garden would suffice for me.  Other kids who voiced not wanting a mansion were told that Jesus knew better than ourselves what we wanted, so we're getting a mansion.  I also wondered why we needed mansions in a place where we wouldn't have need for shelter from the rain and cold or a place to sleep or raise a family, etc.  

The other day I was listening to EWTN and the person on the radio quoted this Bible verse, but used the word rooms instead of mansions.  Suddenly, the verse made sense and I didn't feel perplexed and put off.  I also realized how the translation of mansions doesn't even make sense.  Why would a house have mansions inside?  A house has rooms.  It doesn't contain other houses.  

I am pleased to see other translations are using room.  I wonder why some decided that mansions would be their chosen word?