Am I being unreasonable to want my two teenage daughters to want to go out with friends together. It's the eldests 15th birthday coming up and she wants to go to a fancy restaurant instead of the usual movies and dinner etc. It's quite an expensive evening and I just presumed that my younger daughter of 13 would go. The younger one doesn't have many friends at the moment and at weekends finds herself being with her dad and me which I know she finds a bit boring, whilst the other dd is often out with her friends during the day(weekends). I could tell that she didn't want her younger sister to be at the dinner and has asked her if she still wants to go. This has made the younger 13 year old feel awkward and now says she doesn't want to attend. The elder daughter says it's awkward as she doesn't feel like she will fit in. We have just had a heated discussion because I'm maintaining that it's normal to invite your sister ( they are 20 months apart) to your birthday but she's a stubborn monkey and quite obviously doesn't want her there. I've told her that she's selfish and unkind to not want her there. What does everyone else think? AIBU?