Yes, there is a limit for the maximum posts you can create in a day. This is because you are a new user (Only signed up 2 hours ago) and already have 13 posts.
I believe the limit is there to prevent spam. Example: If there wasn’t a limit and a bot signed up, it would be able to post spam messages all day non-stop.
You can also read more about the limit here:
I know you’re clearly not a bot and thank you for your contributions so far. This shouldn’t happen again once you reach the next trust level.
I suggest you wait till tomorrow to post and read the requirements for the next trust level.
To read more about the trust levels, open the menu at the top of the page, press badges and scroll to the bottom of the page.