Tha la for the reply. I do like her. We a sharing laughs and fool around. (scaring and prank each other).

I am controlling myself as much as I can. Sometimes, when I got lost in my thoughts and doing porn in my mind with her, I simply end it thinking that doing so would just brake her and she would lose her bratty attitude that I like.

As you said there could be many possible reasons. But I am sure that controlling is not in them.