Y'all seem to interpret the question way differently from what I think of when I hear it. There's being comfortable with your skin, which I see as almost entirely separate from being comfortable in your skin (Which may have nothing to do with skin at all).

I grew up as a child of the internet, spent many of my days interacting with people on forums, in games, via IM, and through IRC. As such, "talking to people" meant the same thing as typing to them at odd hours of the night. School and family were, to an extent, a distraction from this other world and during The Formative Years I lost somewhat of my ability to straight up talk to people, like openly, with proper communication, and all that jazz.

So when I hear: "are you comfortable in your own skin?", I'm reminded of those days when I was happiest as a virtual creature and I avoided the ephemeral world, where my skin no longer did not exist. Because I was by and large not comfortable in my skin in that world, I practically leaked anxiety and discomfort. I didn't know what to do with my hands, with my eyes. My back would curl forward and my legs would tense up.

No matter that I was not fat (I was closer to skin and bones, but my concern over this wouldn't arrive for another few years). Nor that I was tall (but not too tall). First and foremost, I did not appreciate the idea that I had skin at all, and was not simply a program, a routine, that could interact with words via words and keep to the depths of the web in peace, not having to think about how long to make eye contact for or how firmly to grasp the skin (or do you grasp muscle? or bone?) when performing the handshake function.