Head Blacksmith Opix:
To become an Artisan, you need the appropriate level and token. Your level must be at least 20 to qualify to change profession. To become an Artisan, you need a token to prove you have passed the Test of the Artisan, as well.
I am satisfied with your level, but it seems you have not yet passed the Test of the Artisan. Ask Blacksmith Silvery in the Dwarven village about the Test of the Artisan. She is the judge of the first test. If you ask, she will tell you everything you need to know. After you have passed the test, come to me. I will change your profession to Artisan.