"Am I going to wait ... again?"

Mila's son seems to be the same age as Luther. The siren, who is in his early 20's, couldn't be helped to be mistoken to be the same age as Mila's son because Christopher has been growing and maturing abnormally. 

Christopher was now the same height as Luther, and Luther's baby face doesn't help to prove that he is much older than Christopher. 

On the other hand, Mila, who is in her 30s, treats everyone who is younger than her like a child, as her build is much taller and bigger than anyone else's. 

Mila had been treating Luther like a child, which Luther wished to end now. He wanted to at least make Mila feel that he had the ability to protect her and the power to do things a mature man would do. 

Sadly, so far, Mila orders him to do childish things, like entertain her with his scent, let her pet him, or play toys with him.