When random ass so call friends of my sister claim my niece and unborn nephew as their but they…

When random ass so call friends of my sister claim my niece and unborn nephew as their but they aren't family and I don't like them because I know they aren't her real friends at all. Is it petty of me to feel some type of way about that? One girl who I barely knew made herself my son aunt and I cut her off real quick uh no.