Mary was a young girl, between the ages of 12-14, so when she was visited by an angel and told what her life would be, it is incredibly amazing that she continued to stand there and listen.  She faced her fears, her worries, the things people would and did say about her, and she said simply, "I am a servant of the Lord."  It didn't mean she wasn't scared, quite the opposite actually, but through her amazing faith, she was able to stand bravely, to show courage, and to be the type of person we all should hope to be like.