I'm mildly annoyed by my so's scheduling involving her period
Is she saying something about her period?
Yes. she informs me all the time when she is on her period.
I think it is better for her to say it than not say it. You can help her out and be more mindful to her.
It's ok because she forget to tell me once in a while.
Sometimes people can be emotionally charged when they are on their period. You should listen and be thankful she is telling you.