If you have passion, age is just a number. I’m turning 50 this year and bootstrapping a startup alongside my consultancy business. Whether to take the “safe” option of a job I can’t help you with.

You’ve struggled to make things work on your own and the good news is it’s incredibly hard to do so, it’s not you.

I think it’s worth either broadening your skill set beyond development or looking for partners who complement you.

I’d also recommend exercises in strategic positioning and value proposition design to help target viable markets with a desirable product. Pointers available on request.