Did Sarah have faith that she would have a son?

Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised.

And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.  Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women.  Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also?  And the LORD said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old?  Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son.  Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.