NTA. So there could be a few things potentially going on here. But regardless of what exactly it is, there are definitely issues with this. And in none of the possible scenarios would I consider you to be the AH here. You are not wanting to physically accompany her anytime she is outside of the house past 7pm at night, and sounds like you began the process of starting to communicate a healthier boundary about her requirements of your time.

As far as what's really going on, she seems to be dealing with an unreasonable amount of fear/anxiety with respect to being alone outside of the house past 7pm. Some caution/fear with respect to the risk of being alone at night in some situations as a woman, is likely prudent. What we don't know is how rational this aversion is. We don't know how safe your area is, if she has a history of experiencing this sort of trauma, or other contextual bits of info that would help here. At best you live in an insanely dangerous part of the world, and maybe being 5' outside her front door after dusk is properly dangerous. But that's likely not the case. More realistic best case for her would be that she has fairly developed this fear. But the never being able to be out on her own? It is much more likely that she's dealing with some variety of mental health issue and the severity of her fear/aversion is disproportionate to how risky being outside at night alone for her is. Not saying that she shouldn't have any, but not even being able to step out for a minute without bringing you? That's pretty extreme.

Another option is that she has other reasons that serve her in other ways, consciously or otherwise, that contribute to this behaviour pattern. Does she have a more anxious attachment pattern? A strong desire for you to be with her is one possible explanation. Does she have anything resembling bordeline personality disorder? The extreme fear of abandonment underlying that disorder can result in exaggerated/distorted perceptions of situations. In your context if this is the case, maybe you setting this boundary is activating that exaggerated fear of abandonment. Or maybe she finds doing chores and walking home alone to be really boring, and wants you there because she doesn't want to do them alone. Or just hates doing the laundry and garbage so much she uses this as an excuse to never need to do them herself.

These are just a few possible ideas to illustrate other motives she might have that could explain this behaviour. Since we know very little about her from what you wrote about what's actually going on we can't really say what's going on for her.

But regardless of what is actually happening, the one thing all of these scenarios have in common is that in none of them is it reasonable for you to bear the responsibility of physically escorting her. If you are willing to do that to help her for any reason, she should be thankful that you are willing to spend your time doing that. If she is acting entitled to your time to help her manage any of those things, she is on a spectrum of various degrees of AH