Ask HN: Advice on starting an open source coding project?

Hi,

I'm new to programming and I'd like to work on a personal, open source project around the "Quantified Self" area.

My goals are to learn more about programming and to also develop a useful tool for myself.

The MVP will be a web server that will send me text messages daily asking "how many hours of cardio did you do", "did you go to the gym", "how many hours of focused work did you do", etc.

Then, I can reply by texting the answers back.

I want to store this in a database and build a frontend that'll let me see this data in a calendar view.

Eventually, I want to make the text messaging feature "smarter", add more integrations (so you can communicate through whatsapp, etc.), add an export to CSV feature, etc.

I've gone through a couple of JavaScript books, so I'll start off with JavaScript, ExpressJS (or should I use an alternative?), the Twilio API and AWS RDS.

How would you start a project like this?

Would you first write out a detailed list of the requirements and then create a sketch of what the API should look like and then start coding?

Should I look at GitHub to see if anyone's done something similar to this?

Should I put more time into thinking about the technical choices I'm making here (with AWS, ExpressJS and JavaScript)?

Thank you very much!