I think the process never really stops.
Because, on top of the weight loss, we are still changing as we age and move on to new activities or life styles. For example, post menapause you stop putting weight on around the hips and it migrates to the tummy and back

.
I suppose there comes a time when looking at oneselft in the mirror becomes an unhealthy obsession, but for now, like you, I can't quite believe what I see in the reflection