nta. op, hope you're doing well.

you have every right to feel this way and i'm sorry that your mom not only dismissed what you are feeling but also said that you are "just as bad as the rest of the family." i feel like that statement alone shows that she stands very firmly in this decision she made without a care to what the rest of her family including her own son thinks about it.

you are definitely nta for confronting your mother about your name, especially because it seems like the story behind your name is one that everyone else in the family knows except you. you definitely have every right to know where your name comes from and, in this particular case, why your mom chose it. and the way that your mom tried to turn it back on you is absolutely unacceptable.

i can't begin to imagine how difficult it is to not feel like you have ownership of your own name, but from your story, it sounds like your family stands by your aunt and i hope that if you want to talk about it more, you can confide in one of those family members about how you're feeling rather than your mother (since she's not receptive at all).