Am I really?

It has come to my attention by way of my insecurity that not one of my family members seems to think that I'm worthy of taking care of their children if something should happen to them. I'm pretty much hurt by this. I realize that I have always been against having children but that is only for me. I don't think that others shouldn't do it. I just don't want to be a mom. That being said, there are children out there that I would not only be willing to raise, but would be super happy to see on a daily basis. I have the means. I live in a house that is large enough and in a safe neighborhood. If the schools couldn't provide a good enough education, I can afford tutors or even private school. I'm fun (god I hope I'm not lying to myself here). It was a pretty big blow when my brother and his wife never approached me about being in their will, especially since at the time I was making more money than I knew what to do with. Then my cousin didn't pick me either. Nor did who I thought was my best friend (no, it wasn't the lack of being chosen that changed our friendship, I'm not that pathetic) I get that there was probably a time when I wasn't the best choice, maybe people thought I'd be dumb enough to give the kid a tattoo or piercing at a ridiculously early age but at this point, still not a one has approached me and said, 'would you be willing to parent my kid(s) if something happened to me/us?' It makes me think that perhaps I need to take some stock in my life and figure out what it is that I'm doing so wrong in the eyes of  others. What exactly is it that makes me so unworthy / undesirable?