It could be translated also as you have suggested here. The verb ללכת can be used to mean "go" or "walk" it is mainly just used as ללכת ברגל when you need to clarify that it was in fact "on foot."
oh because it marked me wrong. would I definitely be understood if I said this in Israel?
Yes, היא הולכת ברגל makes it very clear that she is "walking," not just "going."