does how a person takes care of a pet indicate how they would take care of a child?

So my GF and I were talking about having a child a few years from now. And lately I've noticed she doesn't really take care of our cat. I usually have to make sure he has water and clean the litter box and puke off the floor. She feeds him but never on schedule. I'm constantly trying to keep an eye on how much he's eating so he doesn't get anymore overweight. She usually takes him to the vet since she's got more free time than I do but I'm usually the one to make sure he takes his medicine. I'm honestly wondering if this is a bad idea. Like I understand a child usually means rearranging your life a bit but I'm thinking I'm going to become essentially a single parent.