Some people get it, and some people don't.
My mom asked me once, ie she initiated the comment, 'would I want her to call me her daughter?'.
I have not bugged her, because at 80 her memory is not ideal at any rate. She introduces me as her son, but considering I still look like a male even if I am wearing jewellery and carrying a purse, it doesn't seem enough yet.
But some people simply will not get the level of importance.
It just means you need to fail to recognize something that is important to them.
Call your mom by her first name and think nothing of it and don't defer to her being older, treat her as just another person not deserving special mention. Talk to her like you would any other human you had no reason to defer to. Do the same with your dad. If his name if Frank, call him Frank and address him as if he was just someone at work.
My sister for instance, I could just tell people shes a secretary in an insurance company. She's NOT a secretary of course, she's a highly skilled professional in the insurance business, she is not just a receptionist by any stretch

Acceptance means accepting. Platitudes and bland offerings of lame support are not acceptable and not a reflection of acceptance. "oh we will always love you". Fine then, show it, should be the correct response.
It doesn't take any magical effort to refer to a person correctly. It also takes no effort to refrain from giving them any credit either.
If they want respect from you, it runs both ways.
I don't expect anything from strangers. If I look male to a stranger, I don't hold it against them to think I am one.
My friends and family KNOW I am female, know precisely why, because I told them in no unspecific terms.
That's the biggest hell of transition though. You will have to grin and bear it and realize you get nothing out of hiding. The sooner you find out who will hate you the better, the sooner you discover your real friends the better. The sooner you are not worrying about it the better.
I tell everyone it is not a secret, I don't want them acting like it is, they can tell anyone they danged well feel like it, I am not going to bring it up ad naseum though. I only mention it when it matters to me. I have no privacy settings set on my Facebook page. The whole world has access to me.
Every time someone that knows me, refuses to treat me as female, they go on a list of people who have no reason to expect getting credit for anything in their lives. Sorry accept me as I am, or none of your life impresses me either. I won't extend acknowledgement of professional credentials etc. You're a lawyer? whatever, a doctor? whatever, don't wait for me to care what letters follow your name. You won some award, really? I hadn't noticed.
Sir and mam are privileges I can revoke.