I started mountainbiking about 10 years ago - once a week. I got okay. Never great. Had a bad crash. Ride rarely now. Haven't been in the woods in ... well, in a loooooong time. My own head is my worst enemy in the woods. Total freak-out with obstacles. Yeah. I'm a newbie. I suspect I always will be.
On the road....I've been riding for about 15 years. Sometimes, things click and I can say "hey, I'm a cyclist and I have my act together about this." Sometimes, I ride with folks who really have their act together, and I feel like a total dork. Then I say "I'll always be a newb."
So, yeah. Being a newbie is a state of mind. No one hands out diplomas or anything.