This advice is about a million dollars too late, but... don't write a single line of code until you know who your audience is. Also, don't spend money on marketing until you know you have built the correct product.

At this point, all is not lost. But stop coding, start talking to people. Ask them what they do and do not like with what you have so far. Iterate and improve based on those conversations until people start giving you positive feedback, then and only then try to find more people to sign on. Once you have a decent initial audience who are all giving positive feedback... that is when you start marketing.