“for she was 12 years old.” This describes why she could walk even though she had been referred to as “little” in this and other Gospel records.
“greatly amazed.” The Greek text is “amazed…with a great amazement,” which is the figure of speech polyptoton, the repetition of both noun and verb forms together.a It highlights the degree of astonishment, they were greatly amazed. Some manuscripts add “immediately,” and have “and immediately they were utterly amazed.”
[See figure of speech “polyptoton.”]