My roommate's mom still calls her 'he' a lot, her main excuse for that is that she's old and its hard for her to change gears and keep her pronouns straight, in fact, once she said it would be like if my roommate started calling her mom George. My roommate passively aggressively started to mess with her by calling her George a few times after that, was funny.
So yeah, in other news if adults dont understand it well its one thing, but if they can accept your change openly as you be yourself without any anger towards you its much better. Trust me not everyone has the luxury of a clueless yet accepting parent