Around the two year mark. But not consistently. I still don't consistently see it, or rather, I sometimes see old features which no one else seems to notice. Stare for 30 years at your own face and it's just burned into your brain, it seems. Takes a lot of time to see something different. Try different angle in the mirror, unexpected angles. They will show you an angle you never seen before, making it more objective.
A month ago, I was shopping. Standing at a shelf, I suddenly noticed from the corner of my eye, someone staring at me. I look straight at it to see why that woman was looking at me, and it took me about 1 second to realize it was my own reflection in a mirror. In that 1 second I saw myself objectively before I realized it was myself. It was a very strange experience. I expected to see someone else, and for 1 second I really thought I did. The brain seems to project it's own body image after a while, that's why it can long to overwrite that image with a new one. And the longer the changes take, the slower it seems to go.
When I was in the hospital for SRS, I didn't see myself for a whole week. Never had a look at my face. All this time I projected how I thought I would look. On day 7 I did look in the mirror for the first time, and I really noticed that I looked better than the image I projected or remembered. So if you want to know and see changes, avoid mirrors for a couple of weeks. Good luck!
The body image I had of myself was very strong, and it was reinforced by memory, 30 years worth of looking in the mirror, reflections and negative thinking.