Didn't Shelby have any friends of her own? She was always hanging out with her mother and her friends.
shareI always wondered about that as well, but it seems Shelby was more of a mama's girl and gravitated towards her mother's friends. One could say that since Annelle was closest in age to Shelby than M'Lynn that could be considered Shelby's friend.
You mustn't give your heart to a wild thing
I always assumed that she had made a life for herself elsewhere as a young adult. She had nine bridesmaids, including her cousins, so she must have friends.
The ladies are into everybody's business there in town, but they don't know Jackson. He had never been to the festival, but Claire's cream cheese cousin knows him.
Louis meets Shelby but hasn't seen Ouiser in years.
All oif this suggests that Shelby's life is centered in another community with limited overlap to her hometown.
I think she was just hanging around the cast when visiting her parents. And we really see only maybe ten days of her life.