I think there is a catch-22 between being referred to as a girl (young, possibly inexperienced, lower in professional status, etc.) and being referred to as a woman (older but still rather age-ambiguous, more experienced, etc.) It may just depend on the context in which each is used and the connotation associated with it. "I met this nice girl at the market" may be totally different from "They gave that new girl a bigger office." However, there may be situational clues we pick up on when deciding which word to use... such as how old does the female appear? Do we know her real age? Is she with her children? Is she married or is she still cruising college parties? I suspect there is tension between the desire to be taken seriously and respected professionally and personally, while wanting to be perceived as youthful due to society's pressure on womens' age and the beauty industry that profits from it. My two cents.
That being said, what about "ma'am" and "miss". Personally, "ma'am" makes me feel older than I am...