High Prefect Drikus:
Basically, to qualify as a Monk, your level must be at least 20 and you must pass the Test of the Monk.
I am satisfied with your level, but it seems that you have not passed the Test of the Monk yet. To take the Test of the Monk, go to the Orc named Gantaki Zu Urutu of the Orc village. He will tell you everything you need to know. After you pass the test, come to me and I will change your profession. Use the Gatekeeper to go to the Orc village.