Whether published or not, those first pages are extremely important. Those are the pages, and scenes, that make or break the book and either grab the reader or send them packing–whether you’re selling the book in the store or trying to get an agent.
What do you do if you know those opening chapters are slow?
When it comes to revisions trust your gut. You will not have an opportunity to explain your book to readers, you need to let your book speak for itself. If there’s a problem, you need to fix it.
A build-up can actually be a very fast entry to a book if it’s done right. The pacing of a good build means that even if there’s not a lot of physical action, the reader feels it build as they go and knows that things are happening. The action is psychological. If you have to explain your build it’s not working.
A rule when it comes to editing is if you see a problem, agents and editors will too. Don’t risk rejection because of something you already know needs to be fixed.