You can edit your DS 160 before you go for your finger print verification.But if you feel you are too late to edit the DS160, better do not edit.I made couple of mistakes in DS160 which I recognized after my finger prints.I was in great tense during my visa interview about the mistakes and the visa officer asked me regarding my mistakes and I admitted that I made mistakes honestly and then I answered the questions without hesitation. My visa got approved. I feel DS160 is a kind of form to understand your intention for the visa you apply.I feel you should not worry about the mistakes you did before the interview, if your intentions are clear you should not worry much.Wish you all the best for your interview.