Calling her “incredibly self-centered” seems like a bit of a leap - she’s clearly been having a rough time of it......
I think my attitude towards Mother’s Day is unusual, and possibly relates to the fact that I used to be a church-goer, and in the churches I attended it was a big deal and an opportunity to celebrate all mothers, and indeed all women really.
So I do usually text all my female friends and family who are mothers to wish them a happy Mother’s Day, and especially someone who is a new mum.
Having said that I don’t do more than text - I wouldn’t organise gifts for them or anything like that.
My own mom wished me a happy Mother’s Day just now.
So I think it depends what you were hoping they would do, really. I wouldn’t expect a massive fuss, but some acknowledgement that it’s your first Mother’s Day would be nice. But maybe they don’t really observe the day?
If you get on with them well otherwise I wouldn’t take it personally.
You sound lovely @Lovelydiscusfish and you reminded me that my mum and my sister also wished me a happy Mother's Day in return. My SIL also messaged me from the US to wish me a happy Mother's Day.