Youthful is not the same as rude or immature.


And it does seem like she will always play mind games with you, especially since its her version of being "human".


So either accept this woman likes to destroy and toy with your ego, without a care for how it affect you and accept her as is.


Or accept that this is how she is and move on.


Either way you have to accept that she wont change, people don't just magically do so, especially not at her age.