If Disney movies are to serve as any indication, the relationship between a stepmother and her stepdaughter can be wrought with conflict. While there are plenty of happy blended families with loving step-relationships, the adjustment from "who is this lady my dad likes" to "she's practically my own mother" can take quite some time, moreso if the kids are on the older end.
Of course, the street goes both ways, and while stepmothers can be cruel and manipulative in fantasy and real life, the stepchildren can also play the game and make things a living hell. All this is to say, it's a tricky dynamic, and even the most positive situations have their growing pains.
That being said, if both parties have thrown in the towel and conceded to a prickly relationship, it's only likely to grow into something far worse.
"WIBTA if I suggested to my fiancé that his 12 year old daughter doesn’t come to our wedding and we make it an adult only wedding?"