

Those things are not mutually exclusive. When you lie to yourself, or just avoid looking too closely at something, you can effectively mislead yourself without actually knowing it. Then you do become that oblivious. This is called repression, and it’s how I ended up not recognizing my own gender identity for over thirty years.
That’s still missing some of the nuance. The way you’re phrasing it paints a picture of having known at some point and deliberately burying it. This can also happen, and is called suppression. But it’s also possible for this to happen without any conscious awareness from the beginning, which is repression. In that case, there’s no “starting” to believe it, because you never had anything else to believe to begin with.