In "The Crucible", why isn't it difficult for Ann Putnam to believe that Goody Osburn is a witch?

Goody Osburn is accused of witchcraft in the very first act of the play.  When Tituba is manipulated into confessing that she saw women of the village conspiring with the devil, Goddy Osburn is one of the first names that she mentions.  Upon the mentioning of her name, Ann Putnam responds by saying, "I knew it.  She were midwife to me three times."  The important thing to remember here is that Mrs. Putnam had seven children die at or before birth. Therefore, it is not difficult for her to believe that Goody Osburn is a witch because she feels that she had something to do with the deaths of some of her children.