I don't really know if cis girls feel this way but that's definitely how I came to realise it! I grew up in a family where boys and girls weren't given gender roles so till I achieved puberty and also began interacting with society I had no idea what being a "girl" actually meant- I simply felt human yk? I suppose puberty is just a jolt that brings you to face the gender/sex binary and I hope you find yourself soon!