How will only 2 years of foreign language affect my chances at top colleges?

@bomerr So what I am understanding is that colleges don’t care that I am Korean or whether I speak Korean at home; they only care about the foreign language credits and my proficiency of that language.

Rule of thumb is that colleges want to know your proficiency, through an AP score, an SAT2 score, or a college level course.
Exception: Top 10 colleges care if you’re Korean/Chinese and took a Korean/Chinese subject test for a foreign language if in fact you speak it at home (they frown on it a lot actually if there’s no “really foreign” language although it’s a real plus to have both the heritage language and another one, like Korean and Spanish in your case.)
Top 100 won’t care as long as you get a good score - which ranges from 640 to 700 depending on the college and on how many semesters you want to skip. Some colleges (like Yale) require a semester of foreign language no matter what level you reached while others will easily grant you foreign language credit.
Note that College Foreign Language classes are intense, with between 1 and 2 years of high school material covered in a 4 or 5 credit semester at the beginning level, and about 1 year covered in a semester at the intermediate level ( preAP to AP).

@redpoodles The average European student starts taking foreign language classes (often English) earlier than the average American, true. However, upon leaving HS, the level of English proficiency varies by country. Almost all Scandinavians and Dutch (as examples) are proficient in English not because they started English studies earlier than the Spanish and the French, but because, IMO, all their foreign media is subtitled instead of dubbed. Even their pop music icons perform their original compositions in English in order to reach a market outside of their home country.