Definition: denoting a trial impression of a page or printed work
Definition: evidence establishing a fact or the truth of a statement.
I received the proof copy of my novel. This established the fact that my novel is soon to be published.
I am stupidly proud of it and of course, there will be the fanfare of a proper launch and endless tweets/social media posts and yada yada yada when the time comes (there are some typesetting errors to correct which is frustrating but part of the process), but for now… just enjoying the feel of it.