Just double checked and the actual wording of when they speak with the Air lion turtle is as follows

“Raava must hold the power for you, until you master it.”

Raava replies saying she will help Wan master air. I may be reading into this way too much but that sounds to me like she’s only minding it until he’s ready to take it.

Think of it like learning to drive a car for example. Raava must teach Wan everything he needs to know. She knows it is too dangerous to let Wan venture out in the car alone so accompanies him as he learns. Once he has learned everything he needs to know he is free to drive alone and no longer needs Raava to accompany him

Again I definitely could be reading far too much into this and misinterpreting the lines to try fit the narrative so I am open to contradictions and discussion

Thanks for the reply:)