It doesn't work like that D: once you choose a job you cant go back :x If you wanted to stay a novice, just dont change your job.
However, I think the GMs still offer a service where for 5$ ad credit you can rollback a character and change your job. I really don't think it's worthwhile for your case though D: Just make a new character!
EDIT: Or! You can lvl to 99, rebirth yourself, and THEN stay a novice 8D that is an option as well