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

This occurs in Act I when Parris is essentially
interviewing Tituba about what has happened out in the woods. He is asking who was with
the Devil when he came to the girls while they were out in the
woods.

Mrs. Putnam claims that Goody Osburn's experience as
a midwife is proof enough that she might very well indeed be a witch. You see, Goody
Osburn acted as Mrs. Putnam's midwife 3 times. In each case, the babies "shriveled in
her hands". Mrs. Putnam seems to have a fear of Goody Osburn that she suggests might be
a witch who causes children to die. But, it is important to note that Mrs. Putnam has
now lost at least six children.