It's been my experience that arguing people out of firmly-held opinions is a very hard task. Look at how we deal with religious zealots, flat-earthers, or even political opinions. I've seen no amount of reason, compassion, logic, or debate will change the mind of someone with an entrenched opinion.
The answer here is to approach it less like trying to convince and more like a discussion. That will involve listening to what she says, understanding it, and then trying to see her side. (In this day and age, it seems to like too many discussions don't do the first, let alone the second and third.)
In this discussion, the bell's been rung, so there's no retreating from it. She knows you plan on not having kids, so there's no way to have that discussion for the first time again. You can re-open the discussion after things are a little calmer and start off with, "I understand you blame yourself for my not wanting to raise kids. Can you help me understand why you blame yourself for this?" Now you're asking for help, not trying to convince. In my experience, people are willing to help but very unwilling to open themselves to be talked out of their beliefs.
Let her talk. In discussions with my parents, it's become apparent that we have VERY different interpretations of the same events. What may have been traumatic to you may be a non-event to Mom, and vice versa. The important thing is for you to let HER talk, not for you to argue with her or tell her that "That's not how things were". You want to understand her position, not argue her out of it. This may take multiple listening sessions from you.
After, and only after, she has explained her position and you understand is it time for you to respond. When talking with others, I've come to realize that others will only listen after they feel heard. It's not the time to do a point-by-point rebuttal; it's time to sympathize and explain why you don't want to raise kids. If it has nothing to do with how you were raised, then it's the time to tell her that. "Mom, I understand why you feel this way, and I really appreciate your taking the time to talk about it. It's not a question of my childhood or how good of a parent you were. You aren't the same mother that yours was, and I won't be the same parent you were. That's just how things are; we're not clones of each other and times are different.
"I'm not looking at parenthood because..." and then lay out your reasoning. Maybe you are too focused on your career. Maybe you just don't want to raise kids and don't see it as being rewarding. Maybe you think the world is overpopulated and don't want to contribute. Maybe the Flying Spaghetti Monster told you not to. It doesn't matter what the reasoning is; you want to first of all ensure that she feels heard and then you want to take the position of helping her and that help consists of your reasoning to not be a parent.