The UK screening of the movie will end up being renamed "Crazy Rich Orientals" for a reason.
...Only because in the UK, the term "Asian" is reserved for Indians and Pakistanis, whereas "Oriental" is what they call East/Southeast Asians.- Jossed.
Peik Lin's Family is only "Rich", not "Crazy Rich".
There are multiple hints, including her Mom (who fits a certain stereotype about suburban lower middle class Singaporean housewives), her Dad being a State University alumni (rich enough to afford a foreign education, not rich enough to buy your way into Harvard), and her family's house being a renovated house rather than a full estate mansion. She might know the Youngs and be tolerated by them, but she is certainly not a social equal. In the book, she addresses how her family despite being rich, isn't "crazy rich" like Colin's family and the like.