Yea, but then you have to define what "knowing you exist" means... Does it mean you have a model of the world and you know your place in it, meaning that you can predict what would happen if you would do this-or-that in your current state? That doesn't seem impossible for an AI and you could argue some of the current reinforcement AIs have a model like that and act according to that but it's not as accurate and complex as humans have. So maybe it's a spectrum depending on how accurate your model is and we just don't have a human level consciousness just as we don't have human level intelligence yet.

Not really, knowing yourself to be an entity is pretty straightforward unless you want it to be a philosophical argument.

my program that prints "hello world" to the screen is then conscious?

Does it make a convincing case?