I Missed It!

This morning, after Nathan and I got up and I had breakfast, we went into his room for some tummy time.  I set him down on the floor and then turned to get some toys for us to play with, when I hear a soft "tha-thunk".  I turn back, and Nathan is staring up at me from his back! 
"What???" I think. "Didn't I put you down on your tummy and now you're on your back.  Did you just ROLL OVER for the first time??  No, it can't be! I missed it!" 
I turned Nathan back over on his tummy.
Me: "Nathan did you just roll over? Show Mommy what you just did!"
Nathan: *grin*
Me: "Show Mommy how you just rolled over!"
Nathan: *bigger grin*
Me: "Nathan, did you just roll over?  How did you do that?  Come on, show Mommy how you did that!"
Nathan: *yawn*
Me: "Please, Nathan, show Mommy!"
Nathan: *lays head down and starts sucking on his hand*
Me: (thinking) "Maybe I was just confused.  Maybe I just imagined that, because I didn't actually SEE him roll over."
Me: "Nathan, show Mommy what you did!"
Nathan: *starts rubbing his eyes*
So I went to feed him 2nd breakfast and put him down for his morning nap.  Maybe we'll get a repeat (as confirmation) later today or this week.  I'll keep everyone posted!