I haven't been born or raised in an English-speaking country, so I feel like saying that I'm a native speaker would be deceptive. On the other hand, saying that I'm proficient is an understatement.
English is dominant in my day-to-day life, I'm very much immersed in the American media, I get all the cultural references and jokes. I feel as comfortable when I speak in English as when I speak in my native language. Non-natives never suspect I'm not a native, though natives do sometimes pick up on something after we talk for a while.
I'm writing a CV and I'm looking for a suitable label. Usually I simply stated that I have a C2 language certificate but since I've gotten the certificate I've improved and - as I said - now it kind of seems as an understatement. Any suggestions?