Quick challenge: should you start thinking about chapters? It is entirely possible to write the entire book without any chapters (or, depending on your point of view, as a single chapter). To quote a literary great:
Life doesn't happen in chapters — at least, not regular ones. Nor do movies. Homer didn't write in chapters. I can see what their purpose is in children's books ("I'll read to the end of the chapter, and then you must go to sleep") but I'm blessed if I know what function they serve in books for adults.
Sir Terry Pratchett
Now, part of this comes down to your writing style: some people will start the story by writing out a list of events, and grouping them into chapters to write. Some people will just sit down and start typing, never knowing when the next scene break will be.
Furthermore, it also depends on the style of your story. A story set across a long period, with plenty of time-skips — for example, a cross-continental journey, consisting of large swathes of boring walking/riding interspersed with brief moments of intense action; a series of snapshots of a person's life from their birth, education, becoming famous, becoming infamous, and through to their eventual death; or an entire year of schooling — will lend itself well to being broken down into chapters. On the other hand, a continuous story which tracks the frantic few hours of a protagonist trapped in an unfortunate situation of scenario may benefit from not having any chapters, or even any time-skips/scene-breaks.
Consider also that in certain cases, the break between books wasn't even finalised until after several revisions of the story had been completed.
In short, I would suggest continuing to write as you currently are. Once you have your [first/next] (delete as appropriate) full draft of the book ready, read through it and decide if you need/want chapters. If so, then go through, and identify suitable chapter breaks, with the assistance of your hash-tags.