Why was della worried that jim wouldn’t like her with short hair ?

because della loves jim or i think

closer examination, however, finds the mcdonald's kind of job highly uneducational in several ways. far from providing opportunities for entrepreneurship (the lemonade stand) or self- discipline, self-supervision, and self-scheduling (the paper route), most teen jobs these days are highly structured — what social scientists call “highly routinized.”  

true, you still have to have the gumption to get yourself over to the hamburger stand, but once you don the prescribed uniform, your task is spelled out in minute detail.