There have been a couple threads around here about word count/page count ratios. I think the average answer was 300-400 words for a printed page. A program like MS Word will do about 500 words/page, TNR, 12pt. Handwritten averages are more like 250 (per side of the page). So if you're writing it all out by hand, be prepared to fill up two or three standard notebooks. Or more.
My chapters currently run just over 2,000 words, very consistently. It's generally a day's work, called a chapter. Initially they were hard breaks, but with practice, I've been able to coincide them much more often with natural breaks in the story. Every story has natural beats to it, often many of them, where it's convenient to break for a chapter. I've also found naming the chapters useful in giving them a topic to work with. But the important thing is to practice different things till you find something that works for you. And there's no real substitute for that practice.
And that practice will also tell you whether your story is too long or short.
My chapters currently run just over 2,000 words, very consistently. It's generally a day's work, called a chapter. Initially they were hard breaks, but with practice, I've been able to coincide them much more often with natural breaks in the story. Every story has natural beats to it, often many of them, where it's convenient to break for a chapter. I've also found naming the chapters useful in giving them a topic to work with. But the important thing is to practice different things till you find something that works for you. And there's no real substitute for that practice.
And that practice will also tell you whether your story is too long or short.