One of my problems is that I tend to overthink things. In my head, I suspect this question is asking me if I'm a native English speaker, but when I see “professional” I'm thinking, “do I get paid primarily for my English skills?” I have friends and acquaintances who make their primary living as writers. They make money off their novels, create marketing content, and write television shows, plays and movies. They’ve won awards. They have two hour debates over the use of an Oxford comma. They are professional writers.
When you add in the 260 point chasm between my Math and English SAT scores from high school I really don't class my English skills as "professional". I even think I'd be lying if I call my skills advanced. I'm mid-level at best. I could probably get a B on a regents level High School English class. I have average skills so I’d class ,myself as mid-level.