How do I not let things get to me

I’m starting a course next week for 6 weeks. My mum (72) has just asked me, “What about cleaning?!” I clean for her once a week. It’s like she feels put out that I possibly couldn’t do it anymore.

I’m so annoyed that she is being selfish. The first thing she thinks about is how the course affects her, not how good it will be for me. You could write a whole book about her issues and I’d love to talk it all through with somebody one day. But in the meantime, how do I not let this get to me? I don’t want to be angry and for it to ruin my day.