Not sure if this is the right place to post

I'm feeling really confused and hurt due to my mum only telling my brother that she had breast cancer. She's known for months but only decided to recently tell me. My mum insists she didn't tell me because she didn't want to upset me and because I have a family to look after. Has anyone experienced this? I feel so hurt by this but also selfish because my mums really going through it at the moment