How did Curley's wife's dream of being an actress affect her in Of Mice and Men, and what change did it cause in her behavior?

In describing the dead girl, Steinbeck concludes with:

Now her rouged cheeks and her reddened lips made her seem alive and sleeping very lightly. The curls, tiny little sausages, were spread on the hay behind her head, and her lips were parted.

Curley's wife spent much of her time alone because there were no women for her to associate with and the men shunned her. She has no inner resources. She is probably only semi-literate. There was, of course, no television in those days and very little on the radio to interest a teenage girl. She must have spent many hours looking at herself in the mirror and experimenting with makeup and hair styles. The curls were certainly not natural but were the result of much time and patient effort with a curling iron. She was evidently copying young Shirley Temple, who was a super-star at the time and noted for her blonde curls, which were likewise artificial and had to be restored every night, although the public was not aware of this. 

Steinbeck takes great pains to make the reader aware that Curley's wife is a very young girl. She was hanging around the Riverside Dance Palace in Salinas when she was only fifteen, as she tells Lennie in the barn, and married Curley shortly after nearly leaving home with two other men. So she is only fifteen or sixteen. Steinbeck apparently wanted Lennie's victim to be extremely young because an older woman would know better than to get too close to Lennie or to invite him to feel her hair. Also, Lennie is attracted to small things and would be attracted to a young girl. Steinbeck even gives him the last name of Small. Steinbeck probably invented the little curls to suggest a visual comparison with Shirley Temple, who was only nine years old when Of Mice and Men was published, but had been making three or four movies a year for the past several years and was world-famous. 

Curley's wife is terribly naive. She wants Lennie to stop stroking her hair, not because she senses he is becoming sexually aroused, but because she doesn't want her curls to get undone after she had spent so much time perfecting them. 

"Don't you muss it up," she said.

"Look out, now, you'll muss it....You stop it now, you'll mess it all up."

There are other reasons why Steinbeck, in plotting his story, wanted to have Lennie to kill a girl who was very young. George feels compassion for her when he sees her lying there dead. He realizes the enormous wrongness in a pretty girl having her life snuffed out, along with her hopes and dreams, however unrealistic, by an imbecile who has no future and is becoming a menace to society. This is one of the reasons George decides to shoot Lennie.