The real FU is your interpretation of things.

When I was about 10 my mom told me she wished she never had met my dad. When asked about me and my siblings, she was like - eh. This is not what's happening here.

You are literally overthinking this to find the bad in it. Reframing it to make yourself some kind of victim here. You're not, she's not, and the dog did you a solid.

You had ZERO investment at that time - none of anything you had happened had happened yet. And unless she's saying she wished the dog picked differently, all this means is that her system worked.

In fact, that's the thing to take away from all of this: her system worked. So be glad she had a system that worked for her (for both of you, really). Whether it was a good system doesn't matter.

And stop framing it like she would have thrown away everything you built up just because the dog had a bad day - you hadn't built up anything at that time and no one can see into the future like that.