There are no health benefits to smoking or vaping as opposed to just not smoking. I don't know how directly this needs to be told to you, but I think right now you're too deep into addiction/denial to see it.
If you love your girlfriend, sometimes it's okay to trust them on something, especially if everyone else is also telling you the same thing, even if it's not what you want to hear.
So you think she could be right? You just don't want to do it? That reasoning doesn't make sense. If you think she's right you should be stopping right now.