I'm always worried when I feel too good at something, I can't help but wonder whether there's an entire world of knowledge out there I'm not aware of (there usually is).
I also noticed my peers tend to consistently rate me 1-2 points higher than I do rate myself. I'm unsure if this is a good thing, if my peers are overestimating me, or if I'm underestimating myself.
I approach your last point differently however; I find it inspiring to look at people being at the top of their fields; makes it easier to plan a route to ramp up your knowledge to that level as the work has already been done.
That 1-2 point gap crops up in a lot of settings - not just programming, but writing and public speaking and many others.
The common element seems to be hidden process followed by a finished product. Your peers see the code you write (or essays, or speeches, etc). You see the writing process, with all its inevitable inefficiencies and foolish mistakes. No one sees Obama stumbling over his speeches as he gets dressed in the morning, they just see a skilled final delivery.
So without more context, I would guess that you and your peers are rating different things. You're rating every stage of your development, and they're rating the results, or at least the commits.
It's likely that being a better programmer shifts your rating scale down in general. Becoming better at anything doesn't just make you better at doing the thing - it also makes you better at seeing mistakes and areas for improvement. Like, I remember watching jazz education videos by Hal Galper, and one of the things he mentions is that there's a moment where you start feeling like everything you do is terrible, and that this means that you're getting way better because you're now hearing the things you've always disliked about your playing.
I also noticed my peers tend to consistently rate me 1-2 points higher than I do rate myself. I'm unsure if this is a good thing, if my peers are overestimating me, or if I'm underestimating myself.
I approach your last point differently however; I find it inspiring to look at people being at the top of their fields; makes it easier to plan a route to ramp up your knowledge to that level as the work has already been done.