Conscious and the existence of consciousness

I'm beginning to think that my earlier idea that the entire universe had been created this morning was somewhat fanciful and implausible. It was immediately rejected by some commenters, by one of them on the grounds that there has to be a sufficient reason why the world was created this morning (together with a lot of stuff that makes it appear to be much older than one day old, such as dinosaur bones).

OK, but that's a different supposition from the idea that the world always existed, but that my consciousness came into existence this morning.  Here's my puzzle. The world has existed for billions of years, and if consciousness exists at all, there must have been millions or billions of conscious beings.  If my consciousness began to exist in 1955, why then?  Why not in Victorian times?  Why in England?  Why not in the future?  It's completely bizarre, and against the principle of sufficient reason.  And if that principle cannot disprove my consciousness coming to exist in 1955, why should it disprove my coming to exist on 6 June 2012?

Why can't we suppose that my consciousness before this morning was embedded in President Obama, but that all my memories as Obama were wiped out and replaced by 'my' memories?  Perhaps 'my' memories were really Obama's, but they were wiped out and replaced Obama memories when he moved to Obama's body.

This arose out of a conversation with my wife, who was wondering whether reincarnation was a good idea, given that you might be reincarnated as someone who had a tattoo, or a body piercing. I replied that in that case, you would be born with a mindset that liked a tattoo, or a body piercing.  She said that was even worse. I wonder if Maverick has an answer to this, as he usually does.