NC: do I “finalize” it?

I have been NC for 7-ish months now. Unlike many on this subreddit, I kind of went NC by default, not because I was strong enough to do it myself. Basically, my mom gave me the silent treatment after I established a very minor boundary that she didn’t like. It was the final straw in a lifetime of manipulation and fear and I stopped reaching out to her, and that was that. She texted me a total of 3 times since. Once, to inform me about (but essentially blame me for) a medical issue my e-stepdad was having. The second time, on my birthday, with a congratulatory message that looked copy pasted from the internet. The third time, yesterday, texting “Am I correct to understand you don’t want contact with us?”.

All I feel is pain and disappointment. Not once in the last half a year has she even tried to reconcile, or ask if we could have a conversation. In the past, I was always the peacemaker. Always the one to reach out and apologize. The one who, even if I was terribly hurt by her, would put on a brave face and be the voice of reason and calm in the relationship. I bent over backwards in the most unfair situations, just because I was scared of losing my mom. It turns out, the moment I stop doing this, our relationship is just done for. Whether I am in action or inaction, nothing I do will ever be right.

I won’t try to understand her, because I don’t think I ever truly will. I am pained by how cruel she has been, and how little she actually cares for me. I don’t know if I should reply to her message. It feels awful to set the NC in stone. At the same time, I can’t keep opening myself up to her abuse. Even if I respond, I won’t get the compassion and love that I so desperately desire of her. Any wise words of advice from you veterans?