Kimmy, Stephe is as honest as a summer day is long. You are 100% passable. More than that, you can not be distinguished from a cisgirl on looks alone. If your mannerisms and voice match your appearance, you would be all girl.
These posters are your peers, with the same fears and doubts you have. But they have the advantage of life experience. Listen and take in what they are telling you. That will really build confidence!!