It's a bit comforting to know how many others in this thread have also had it as long as they can remember. I'm the same...can't remember there ever being a time where I didn't have it. It also isn't the stereotypical classical single tone "ringing" noise for me, so I didn't ever connect the dots as it being tinnitus until into young adulthood.
Still makes me a bit concerned that I'll lose my hearing some day. Both my mom and maternal grandfather experienced significant hearing loss over time.
No trauma or anything like that here. Some of us have just always had it without a cause!