I'm marking this as NSFW because I'm not super sure if this counts as discussing dysphoria. I don't exactly know a lot about this if I'm being entirely honest. Feel free to tell me if this would have been fine or not :)
I've always considered myself a cis dude. I feel relatively comfortable as a dude I think. But there's a lot of stuff that has me wondering things. For example, like a year ago I told one of my friends "Being a man is cool and all, but if I was given the reins at character creation, I would have chosen to be a woman." That friend told me that was not very cis of me to say, and I kinda just wrote it off, but I still hold to that take as the way I feel. When I am falling asleep and I'm sort of day dreaming, I choose to daydream about the adventures of a female character I've invented. When I play video games, I almost always choose the female option if it's given, because I found it's easier for me to get into the story that way.
However, I feel totally fine being a guy. So like I don't know if I'm gaslighting myself here, one way or the other. It's kinda a thing where there's a possibility I might be trans, but if I were to actually do it, I can't tell if my life would get better or worse. I don't think I would feel safe being trans in my area of the world, for example. So it's like sure I might have chosen the female build in the game of life, but that's not what RNG gave me, and maybe I'm okay with that?
I didn't consider I might not be cis until my late-20s personally. I only realized after I started questioning that I had signs and was totally oblivious to them before. I think some people legitimately know early. But I think there's pressure to conform to that narrative when making cis-facing media because it seems to make a stronger case to cis people that its something innate and unchangeable.
For me, one of the big reasons I never seriously consider I might not be cis is because when I first learned being trans was an option (late high school, and I didn't understand what transitioning entailed at all), I just assumed I was cis since I didn't always know I wasn't (even though I didn't even know that was an option).