USPS has no record of my package??

I went to www.usps.com, and typed in my tracking number i was given, and i get this.

There is no record of that item. If it was mailed recently, information may not yet be available. Please try again later.

How long after it is mailed to me should it take before a legit tracking number will be on their site? Should i be concerned about this?

takes atleast 24 hours to be in thew comp....sometimes longer

Don't sweat it too much. I've had packages that arrived and never at any time did they show up on the shipping services tracking system. In most cases I have found they are a day or two behind, and don't forget to take time zones into account.

sometime they dont even scan the package for tracking purpose.
dont worry bro its all fine :)

Thanks for the replys. I actually was able to get ahold of someone at the USPS after i posted, and they said it takes an avg. of 24hrs to get into the computer.