Also, if your only level 60 is WHM, you won't be able to become a Mentor.

To become a Mentor through Disciples of War or Magic, you need ALL of the following:
• Achievement for 1000 Dungeons, Raids or Trials completed
• Achievement for completing all job quests for any Healer job (up to level 60)
• Achievement for completing all job quests for any Tank job (up to level 60)
• Achievement for completing all job quests for any DPS job (up to level 60)
• Achievement for earning 300 commendations

To become a Mentor through Disciples of Land or Hand, you need ALL of the following:
• Achievement for reaching Level 60 with any Gathering class
• Achievement for reaching Level 60 with any Crafting class
• Achievement for crafting 100 collectables
• Achievement for gathering 300 collectables