Best friend is a bit of a stretch right now but she is my longest friend (time wise, not height wise). She was going to be a bridesmaid and my wedding is in a few months, however I got a message today from her saying she won't be attending as it's on her birthday. It is on her birthday but she knew that when she agreed and I bought her dress. If she'd have said it from the get-go then that would've been fine (I'd have still been a bit hurt but I'd have understood) but the fact that she's turned around now, after me paying for her and her husband and two children's meals for the wedding, RSPV'd yes and buying her dress, AIBU to be pissed off?