I recommend that you do not talk to your mother about this again. Nothing good will come of it. She is trying to gaslight you at best, or she has actually convinced herself that she didn’t do these things. Either way, there is nothing helpful for you there.

But also, remember, abusers often do not want to remember their actions and they want to forget/ignore them and she may have been successful at convincing herself it didn’t happen. Whether she remembers or not does not change that you do, and no acknowledgement or apology can change what happened.

And as a person now long away from my abusive father, I can say that trying to heal based on words of your abuser will never be successful. You have to heal without them and then decide how/if you want them to fit into your life accepting the past as something that is done and not forgotten or even forgiven - it happened and whether you have a relationship in the future should be based on whether you desire one and if they currently are deserving - but remember that you are never obligated to give any time, energy, or space for people who do not actively earn a place in your world.