You are definitely no longer a newbie with close to 20 races behind you. I think that once you get comfortable at the race distances and know what you are doing (or at least you think you do) when you approach a race then you are no longer a newbie. I was racing sub 4:30 half IMs for a few years prior to doing my first full one and didn't do an IM until my 10th season of triathlons so I don't think that I was still a newbie in season number 9 :)

The other easy way to tell is when you can't fit all of your race t-shirts in the same drawer :)