I’ll try to explain as clearly as I can —

The reason I’m creeped out has nothing to do with her age — it’s despite her age i.e., one wouldn’t (I hope) under normal circumstances be creeped out by 64 year old women.

However, what did creep me out is the following —
1. I’ve complained about her dogs a few times.

She’s not only not done anything but has been aggressive in defending said not-doing.

This has been going on for many months.

2. I complained to the HOA.

She retaliated by discussing loudly under my window a few times about the “allegations without any merit”.

3. In the meanwhile, she has commented — very creepily — about —
— The fact that I put up blinds as soon as I put it up;
— The fact that I put up the gate as soon as I put it up.

Most creepily leaving me a note after said above passive-aggressive loud comments within my earshot + doing nothing about it all these months + aggressively defending (actually straight up lying) her dogs’ behavior and pointing out that it’s not a problem even when they show up on my patio after I’ve repeatedly said I don’t want them there.

That’s a whole lot of boundary-breaking = serious creepiness.

Where serious creepiness is not something I’d expect to feel from a 64 year old.

ETA: Her offer is far from a good thing — it’s an arsehole-ish thing seemingly disguised as a good thing (see creepy boundary-breaking passive-aggressiveness).

Sure, we can get into the same semantics about what’s creepy or not for a 30 vs 64 year old by asking about all sorts of other behaviors as well — why not expect a 64 year old to behave the same as a 2 year old? After all, going by your logic, where do you draw the line on when 2 year old behavior is not acceptable from a 64 year old? Or, maybe in your reckoning it is? It’s a meaningless argument.