I'm Asian, too (parents from Taiwan), but I was born in the U.S., so I'm fluent in English and not so fluent in Mandarin (can speak everyday, simple terms, but if I watch a variety program, I'm lost). However, I'm not exactly a banana or an egg tart; I'm more of a mango (a little more yellow, but still white at the core). I refuse to just assimilate into white America as iconoclasm is part of my personality, but at the same time, I've just grown used to some things here. However, I'm not one of those Asians who has forsaken her culture just so she can go to the mall and listen to rap/hip-hop and all that BS. I embrace modern Asian culture -- Japanese/Taiwan styles, food, language, etc. -- but as far as the really old culture goes, I'm not big on tradition at ALL. There are a lot of flaws with how the elders used to think (like having boys are better than having girls or having small feet is important). That's just complete crap in my opinion and should not be perpetuated by the younger generation.
By the way, being mixed has nothing to do with it. It's just how you were raised. Babies can learn any language as long as it's before a certain time, so if your parents had spoken to you purely in your language, then you'd most likely be fluent in that language. But you're right; I DO feel sort of bad when I visit Taiwan and see all the people speaking fluently in Mandarin, a language I SHOULD know. Then again, I think... how well do they speak English? That makes me feel a bit better.