I'd this weird

It’s weird that she didn’t add you in it, I’d see it as strange if mine did that, it seems purposeful, do yall have any harsh feelings towards each other?

^This. It sounds more like a anniversary shout out for her and him lol. Unless you have bad blood between you two I'd expect she would/should have mentioned you

My mil did the same shit but she also acted like we saw her all the time before we moved a couple stages away even though she barely made an effort to see us and always demanded we drive to her house. I already have a toddler and I am NOT packing him up every week to bring him to her house, so I think she’s convinced I’m taking away her son and grandchildren from her

Lmao my MiL does this every year and it’s always accompanied by the photo of them dancing the mother & son dance. She’s literally the only person who celebrates our anniversary (my husband and I don’t), and she always somehow makes it about her, how proud she is to have a son like him, how he’ll always be her little boy, blah blah. Same thing happens on his birthday. It makes me roll my eyes but it’s been 13 years so I’ve gotten used to ignoring it.