The concept of DNF (“did not finish”) is pretty familiar to people who read regularly, but three pages seems far too early to make that call. The general rule of thumb I’ve encountered is closer to 100 - 150 pages.
Some of the most memorable works of literature I’ve read are books I didn’t particularly enjoy for the first hundred pages or more. I stuck with them mostly because I deliberately give books time to develop before deciding whether they’re for me.
My favorite example is A Tale of Two Cities. I didn’t enjoy it all that much until Book Three, Chapter 12. From there, it was smooth sailing. It’s now one of my favorite stories I’ve ever read, and I still think about it often, especially that entire final book.
That doesn’t mean every book takes that long for me. There are plenty I enjoy from the very beginning, particularly stories retold from a character’s perspective, adventure stories like Watership Down, and pretty much any Sherlock Holmes novel.
I understand the idea of putting a book down after a few pages if you don’t connect with it, and ultimately everyone should read however they want. But I do think that, by doing so, you risk missing out on some genuinely great books simply because they needed more time to become what made them worth reading.
Side note: My actual criteria for dropping a book are a little different. I tend to stop when reading it gives me a kind of vertigo or that strange feeling where your throat tightens and you start to feel sick.