What in the world?!?

First let me say that just yesterday at lunch, I was talking with a few of my teacher friends about potty training. I said that there was no way Gavin was ready for it, but that he loved to be involved when Macie did. I didn't (and still don't really) plan to start potty training until next summer at the earliest.
Every day, Gavin is obsessed with closing the toilet lid and flushing the toilet. He sees us do that with Macie all of the time, so that didn't surprise me. Well, lately, he has been saying "pee" and "poop" when pointing to the potty. I always tell him that's what we do in there, but I don't think much of it. This morning, I woke up to cheering because Gavin had peed in the potty. Yes, my 20 month old little boy peed in the potty this morning! Evidently he kept telling Brian "pee" and pointing to the potty. Brian thought, why not, and sat him on there. Sure enough, he peed!
Then, today at lunch, Gavin started shaking. I asked him what was wrong and he said, "poop". He had just pooped and wanted me to change his diaper. Now, I'm not naive to think that this means I should start potty training hard core with him, but if he keeps up the interest, we will let him keep trying.
Gavin was so proud of himself and was grinning from ear to ear. We even had to visit Grandma and Grandpa to tell them the good news!
Gavin has been known to do things developmentally out of order. In fact, just about everything with him has been out of order, so we shall see!