Why is it Halafu and not Kisha?
That's a good question.
Isn't it better to use the narrative tense here? Or is it because we haven't learned it yet?
Halafu, Kisha, kwangu ni mamoja (it's all the same to me). The narrative tense does not necessarily put the actions in order like 'halafu' does, although normally you cook before you eat, of course.