I was in the same boat too. Reading this article brought back a lot of painful memories. Like the author, I only found out years after I assimilated. For a while, I couldn't even look at the flag or say the pledge without feeling depressed.

Thankfully one of my divorced parents married a citizen close to when I started high school. Eventually I was eligible to apply for citizenship sometime late in college.

I still remember the citizenship 'test' I had to take. It consisted of telling the tester: the colors of flag, reading a sentence that said George Washington was the 1st US president, and telling her who the current president was. Ironically I had passed an AP US history course sometime ago with flying colors.