As someone who built a habit tracker, I like it. It looks elegant and easy to use and you seem clear on what you are optimizing for.

A couple of thoughts.

I think it's important to be clear whether you building an app that is optimized for tracking for insight or for change. That is what explains why I took a different approach to designing a habit tracker than you are taking. My primary was for change. Yours sounds like for insight.

The reason to be clear is that it can help you filter out feature requests.

There's only one other example of what you're building that I've seen and thought was well done. http://reporter-app.com/

If you are planning to charge, I would want to know that before I sign up for a free version. "Free until 2021, then $5/month."