I would think that the first stuff moved slower because there was more for the explosion to push.

Could you not also argue that stuff would be moving faster at the beginning because the force driving it would more concentrated. The trouble is, this begins to sound like an explosion in space, which we are assured the BB was not.

Then again, if your reasoning is right, perhaps you have found an explanation for accelerating expansion.

Perhaps you and Finiter are both heading for Nobel Prizes. smile
There never was nothing.