I have two points to add:
#1 I'm 30. On the day of my 30th birthday, I asked a girl (a foreigner) to marry me.
I dated a girl long distance for two years in high school, and then we went to the same college. I had plans to ask her to marry me (after four years, when I was 21) in the spring of our junio year of undergrad. Instead, she cheated on me and we broke up in the winter. It's a different story.
I'm glad I didn't get engaged when I was 21. That four yeaar relationship is a very distant memory now, and (after several other long-term relationships) I'm glad I didn't marry that girl.
What does this girl major in? Grad school is free for engineers, most scientists, and math people. I know people getting grad degrees in poly-sci and psych who are on a free ride with research and teaching stipends. From what I can tell, paying for non-law, non-med grad school is not hard to figure out.
Don't marry her to keep her in the country. That's not what marriage is about, and chances are high that you'll regret it.
#2 My fiancee is Taiwanese. The standard of living and perception of America is quite similar to that of South Korea. I'm not sure she's "giving up" as much as you perceive.
I'm half Taiwanese, and my family is in Taiwan. My mother is the only one in her family who has left Taiwan. My Taiwanese family is very suspicious that my fiancee is just using me so she can move to the States. Her family thinks she's insane because we have no immediate plans for her to leave Taiwan for at least a year (she owns a business there and it'd be hard for her to just walk away).
I'm trying to point out that leaving home to live in the States is not so much a burden as it may be a goal. Keep it in mind?
Good luck.