Well once the first press is sold out, it's sold out, meaning no more new copies will be made. What's left would be the normal edition, which usually either means regular packaging (as is the case with "Mirrocle World") and/or minus the bonus materials that are found exclusively on the first press.
It has nothing to do with a delayed release date, however, as the first press & normal edition are produced & released at the same time, so that on the release date, if you don't manage to get a first press, you'll still be able to purchase the CD as its normal edition.
As mentioned above, first press is intended to be a collector's item...if you're really into the artist & want something more "special" to your purchase, that's the one to get. It's merely a business move to get people to buy the CD asap (or get multiple copies of the same CD).
