I use the term sister as I've grown up in a " blood ≠ family " life , my bio " dad " a woman beater scum and my real dad not related by blood , not to mention always hearing stories of my nana taking in my aunts and uncles homless friends when they were kids , so to me blood is worthless and doesn't mean anything , family is what you choose . And then i always struggled to socialise with my own age group so i made friends with younger kids , they were drawn to me as i was kind and quiet , i think of them as my little siblings and like to think they saw me as a cool big sis , and due to this i view all my friends as family and like to think im everyone's big sister !