I think that you handled the talk well....she doesn't yet see what she has thrown away, her scholarship has been exchanged for a job waiting tables. (not that there is anything wrong with supporting yourself this way, I've done it too)...but tossing away a full scholarship for booze and partying is just so childish and foolish.
I think you may see a major downslide in her in the next few months as her friends move forward and she does not....and i do hope it's quick so she can get the help.