When you are Level 20, go to High Priest Raymond (Gludio) and you will become an Elven Wizard. By l2hub
Steps from the game client
Jewel Collection
Quest that must be fulfilled to change occupation to Elven Wizard. Rosella tells you that to become an Elven Wizard, you must collect the jewels that represent each of the four elements: water, fire, wind and earth. She hands you the fertility period, which symbolizes earth, and asks you to find the rest.