Welcome to Eorzea!

The error message is because there is indeed restrictions on this forum based on what level your character is in the game as mentioned in this official post (which really should be stickied on the main page for the benefit of new players as it's long since become lost among later threads - I only know the link from having bookmarked it at launch).

As your character level is only level 13 ARC sadly it limits what you can do here. The least amount of restrictions are for level 50 and above.

The posting restrictions don't apply to New Player Help and the Technical Support forums however.