I remember to have found particularly easy to read Hemingway's A Farewell to Arms, so that I thought that If I read something by some other writer belinging the so called lost generation, it would turn out to be the same easy.
That was not the case; I found it hard to read those two Fitzgerald's stories, I think due to the amount of vocabulary he uses - sometimes only suitable for the time and places he is talking about - and mostly because of the American cultural conventions he constantly and deliberately falls back on.
movie starred by Brad Pitt and based on Benjamin Button's story, but as far as I remember, in order to feature the just born old man, the film director decided to give him an ordinary baby's size, except for the wrikles in his face. I was shocked when I found out that Fitzgerald really meant a just born man with "ancient teeth" and long beard who speaks just after being born.
In my opinion, the story is a narrative experiment that provides the author with the opportunity to set up humorous situations and play with the hypothetical situation of an human being living backwards in time.
Benjamin Button's story is similar to Poncela's "Cuatro corazones con freno y marcha atrás". Let's not forget that both authors worked as Hollywood script writers for some time.
The rich boy mirrors the main topic in The Great Gatsby. Central to the story is its main character, who as a young man, runs a dissipated, lazy and - at some point - immoral life. He fails in settling down his own life and misses the opportinity of getting married a worthy woman. Later, in a very selfish and arrogant manner, he thinks of himself as capable of giving advice to others. In the end, he feels all alone; forgotten by all his friends and relatives. In spite of his failures, he insists in behaving the same way he used to.
The rich boy is also interesting from the historical point of view as we become priviledged observers of the very rich NY society; those belonging to the very reduced set of people who became rich before the 1860s.
I had the impression that the author himself gets involved in the story as he identifies as a close friend of the main character. Everything is then, told in the third person narrative style.
I strongly recommend you to read some of Fitzgeral's Literature, but be prepared to use your dictionary and your wikipaedia quite a lot.