Teen Behavior: Provocative Clothing
Probably not. It most likely means she's starting to be interested in boys and is trying to be attractive. It also suggests, unfortunately, her desire to be in style. The look of today is very provocative; it sends out messages that these middle-school girls are not necessarily cognizant of or mature enough to handle the responses to.
As her parent, it is up to you to establish limits. Let your daughter be in fashion, but let her know where you draw the line (y'know ... hem line, neck line ... sorry, couldn't help myself!).