I have been very lucky with my two, YS still at uni (due back any moment

) so we will have two months of untidness, strange hours, moods etc. His sister, now 23 was terribly untidy but has changed completely and is more tidy than I am

I am sure yr daughter will come out of it. Perhaps you should try a different approach, untidy bedroom- shut the door! Don't do any washing/ironing for her - I stopped when mine were 18. Don't fill up the fridge, let her fend for herself etc. Restrict the money/treats etc.
Above all be subtle - don't be drawn into the rows. I used to ignore my two, sometimes for days - worked a treat. If she is rude to people just laugh and say 'huh students!! She will get the message.
Good luck....