Partner's parents..

Don't know if it's my hormones that are playing up but, my partners mum posted my scan picture on a group that she's in, asking what people think the sex is? Never mind it's group of strangers and has my full name and birthday on the scan? It's really irritated me purely because it should be posting the photo asking what people think, to people I know? Don't know if I'm over reacting or what but I'm so annoyed:(