How fluent do you think one have to be to be considered "bilingual"?

Do you think that the person must be

1. born in a bilingual country / completely indifferent to native, educated speakers of the language
2. able to write, speak and hear with little to no grammatical errors in almost any situations / able to take college level classes without language barrier.
3. able to conduct any casual conversations with little to no grammatical errors

or worse?

English is not my first language but I'm quite confident myself. And I'm always torn between saying that I'm bilingual or just fluent.

A lot of the times, I think in English and sometimes even dream in English but I also have never spent a single day in an English speaking country in my life. It's weird to know that I'm not a bilingual per se but to think like one. Just wanted to know if anyone had similar experience.