From what I remember of being new, it'll say 24 hours until you're able to post; it doesn't update. (When you are able to post, you can only do so once every ten minutes until you aren't tagged as "new"; this is a measure against spammers and their kin, since one was once able to do 75 threads before a mod was around, IIRC.) Starting new threads is slightly different, and I don't know if that's just an oversight or a deliberate feature. Your first thread in a forum won't make the forum herald's welcomebot send you a PM, for instance, though replying to the thread will.
If you have any questions about what I just said — especially if I used terminology that isn't clear! — feel free to reply in this thread once you can, or PM me (which may or may not be faster). Welcome to TV Tropes!