Noelle didn't think she was too good for anyone. That hadn't been why she left at all. She had been suffocating. That was a fairly sufficient reason in her book but saying so would only make things worse. It was better to ignore her aunt and keep eating.
She hadn't abandoned her family. If she had truly done that, she wouldn't come back for holidays or stay in such frequent contact.
All she had done was move to a different city for the sake of her sanity. Seeing her family less allowed her to enjoy her time with them more when she did see them. What was so wrong with that?
Most people left the nest eventually. Staying in the same town with no future wouldn't make Aunt Tammy any happier. She would harp on Noelle for not getting married like her siblings when it continued to not happen year after year because no one in town was interested in her. That sounded far worse than continuing to go on terrible online dates.