There’s always going to be a little bit of that in any novel. No plot is ever new, so you’re always going to see novels that resemble your own in some way. In truth, there’s only about a dozen novels that I’ve ever read from start to finish and felt they were too much like another novel that clearly inspired it. With that said, a few times I have thought that about a novel, I haven’t necessarily thought of it as a bad thing.
Sometimes I’ll read a new book that reminds me of an old (or new) favorite that I couldn’t get enough of the first time. It doesn’t necessarily need to be a bad thing, because at the end of the day, though there might be elements in common, it’s probably far from being the same book.
For instance, we can compare the Harry Potter series to The Lord of the Rings or to Star Wars or to so many other books and films. It’s always about “the chosen one” fighting (and eventually defeating) the big bad evil hardly-human villain. All of these series have a few things in common, but they’re FAR from being the same.
Remember too, for awhile, fairy tale retellings were insanely popular. I still love a good retelling. One of the things I love about retellings is that even though you technically know how it’s going to end, when it’s well-written, often you’ll still find yourself forgetting the ending and not know how things are going to turn out for the characters.
Now, if you are writing a novel that feels to similar to a book that you absolutely love and you can feel that affection for it leaking into your own writing, it might be worth making the plot feel very different. Changing the setting, the kinds of characters, the premise of the story – all of these things will help make this feel more like your own project. And the more it feels like your own project, the more it will become your own.