You need to have 5 likes on any of your forums posts to be able to apply for staff. Since you just joined today you have none. I think this is to keep complete random people from applying and also a way to get rid of bots. So just make some threads that you think people will like and then try to apply later.
How ever since you were not aware of this system it might be best to wait a little longer and gather some more knowledge before applying for staff.
