Don’t think that things like “rescinding your apology” are necessary - just be done. If you can support yourself, and have friends or other people you can emotionally rely on, I would just simply “stop” with your family. Why “rescind your apology”, that will just start another argument for the sake of trying to give yourself some sort of moral high ground, which it aounds like your mother will not acknowledge.
You don’t need to make a statement about it, you don’t need to announce to them some big decision, just move on. Live a happy life. Be you. Don’t include them in that process if they are not going to be a positive part of it.
15 years seems like more than long enough with a human’s brain to assimilate all other ant colonies and do some hilarious levels of damage to the most ecologically destructive human buildings and apparatuses.