Older cats

Just wondering if anyone has any experience with older cats? Our girl is at least 16 years old and is in pretty good health, just a bit of arthritis in her back joints. She eats and drinks fine and doesn't seem unwell.

She is an indoor cat and is usually fantastic with her litter box. She'd only 'go' elsewhere if she couldn't get access to it or if it was too dirty for her (she likes a VERY clean litter).

After DS was born last year she had more accidents than normal which was understandable. This all calmed down as she got used to DS.

But for a couple of months now it just seems like she poops where she likes. Even if her litter box is completely clean I'm finding poop in our room or in DS' room, or even in the loungeroom. She spends most of her time in our room and I'm pretty sure that often when she's pooped in there, she hasn't even tried going to her litter. I'll be in bed, she'll jump off the bed and go into the walk in robe for example.

I'm wondering if this is the beginning of her getting too old. DH doesn't want to know about it, originally she was his cat and he is very attached to her. He doesn't want to think about her no longer being with us, and I understand it upsets him. But I'm getting really sick of finding poop all over the house and it's only a matter of time before DS gets to it before I do!

Any thoughts?

Is her poo runny or with blood in it? If not, I think it could be behavioural, but I am really not sure.. Is she peeing outside her litter too?

My cat is also and indoor only cat and was around before I had kids. She will be 14yrs old next year.
I would be inclined to take her to the vet and get her checked out, it could be she has lost control or is going a bit senile.
When I took my little one to the Vet she said she seemed well, just a bit stressed and was thinking of prescribing her kitty valium to help her. They may also suggest a particular diet due to her age, I have to get the Older cat food.
I have also started to give her alot more attention now things have settled down with the kids, so I brush her twice a day give her lots of strokes and pats and she now likes it when DS1 show her attention too. It's helped her, so perhaps you could try that?

No blood or anything thankfully, just normal poop. No wee either so it could be behavioural.

Yeah she has the best food, DH insists on that :D We probably could give her more attention. She's meant to have her annual checkup next month which might give us some answers.

She is a beautiful cat so I really do hope it's nothing serious!