Complex sentence: Her parents asked Crawford to dissuade her from marrying, since she was so young, but Crawford not only gave the couple her blessing, she had the wedding ceremony performed right in her own house without having the parents present.
Split into simpler sentences: Her parents asked Crawford to dissuade her from marrying, since she was so young. But Crawford, not only gave the couple her blessing, but also had the wedding ceremony performed right in her own house without having the parents present.