Indulging vs. things taking longer than I thought

Hi there! I’m trying to get my writing side-hustle off the ground by finishing my very first novel. I often make a schedule for various tasks–editing, for example. And then the schedule gets completely destroyed. I wind up at the end of the month with only a third of the work done. Part of the mis-planning is inexperience. I’ve never written a novel before, so I just don’t know how long things take.

But maybe, just maybe, this is an excuse, and my former problems (procrastination, not doing the work out of fear of failure, emotional buffering) are just morphing into an “I don’t know”…”I don’t know how long this takes so it’s okay if it takes all the rest of the year.” Just an advanced form of procrastination, right? On the other hand, it is editing 350+ pages, it’s gonna take more than a week.

How did you plan your days/weeks/months for unknown tasks when you were building your business?