To my mind there's a difference between seeing the antagonist and knowing there's an antagonist.
If the characters know someone evil is behind everything and know who it is, then it doesn't matter if we don't see her or even any lackeys until well into the story. If they know there is someone evil, but you as author want to keep that person's identity secret, then you do need to show that person, or at least refer to her consistently, even if the identity reveal is delayed until the end -- just as in a murder mystery the murderer has to be one of the characters we've seen, otherwise the reader will feel cheated.
If, though, the characters have no idea someone evil if out to get them and you as author give no hint of that person, then it's likely to be harder to pull off a belated reveal, not least as there's less sense of conflict or higher stakes up until then if they always appear just battling chance or life in general.
HareBrain's Firestealer series gets around that unknown antagonist problem by having the evil characters appear in scenes (or, rather, be heard in scenes) where it's not always easy to understand what's going on, because we're not initially sure who they are and what their goal is, but it is made clear that there's malevolence behind things, driving not only particular incidents but also the plot. I've actually copied that idea into one of my books, where it's helped give depth to the story.
In another book I've also played around with giving my characters a supposed antagonist, so there's a focus for their anger, only in the very last pages of book one to show that there's someone else in fact pulling a lot more strings than they realised, and though we've not met him he has been talked about earlier in the story. That then pushes a greater conflict into the sequel -- if the reveal had been made earlier, meaning the characters weren't manipulated in the same way, the first book wouldn't have worked.
So, yes, delaying the villain's entrance is possible, and might be in context the better idea, but I think you need to pin down exactly what advantages stem from that, if any, or whether conversely the feel of the novel is impaired by doing that and if so what you can do to get around the problem. Basically, either way it's up to you to make it work.