I've got some bare bones ideas here: A young girl, 16-18, falls in love with an older man, one who is around 30-35. The man is not perverse/sick/etc. I want it to take place sometime during the 1920/30s. The girl will not be innocent or naive, but she will be well adjusted and cooperative. The love with be genuine, although misleaded. Where can I take this? Keep in mind I want it to be a teen fiction, but "gritty" as my friend puts it. She says I can write a good story with this plot, as long as the characters are real. Can someone help me flesh it out?