That seems reasonable 
Full just means that there is is A LOT of characters on that realm. You can create new characters on the realm, but you will find yourself with a queue times sometimes on peak hours.
the full status indicates amount of avg login versus amount of available player space on server I would suspect although you create a character after realm selection that character storage is stored on elsewhere altogether. based off of your personal character limit of 50 being shared between all realms. could.be wrong though