I know you've asked this in the newbie-forum, but I thought I'd point it out anyway, since you might be able to use it later on too.
When displaying the date to the user the way you do, and even enable him/her to edit it, you also enable the user to send malicious code yto your database or just fake the creation date. So what I'd personally do, would be to omit the date in the form and then on insertion-time in the DB, I'd use NOW(), which is also more accurate. If you use MySQL, search for NOW() on their site.
Hope it helps? Sometimes it can be really annoying to look for the answer, so some time it can be quite fun / helpful to surf around among all the possibilties / functions in MySQL, PHP and such. Look around!