Hi there, I can relate to your question, because I was in similar shoes a couple of years ago. Here's what I'd say:
1) Start where you are. Take stock of what you know. Gather data (like you're doing now) on where you need to go and start moving forward one step at a time. Don't be overwhelmed that you don't have all the skills now (who does??!).
2) Some other folks who answered here gave some smart answers that I will echo. You want to make sure you're solving an unaddressed pain or solving a pain point much better than others. To do that, you can test the pain and you're initial solution by going out and talking to people. Find people by putting up a simple page to gauge interest, by connecting with friends, by using your network. Get out and listen.
3) Create an MVP. Test it. New version. Test it. New version. Listen to your customers; don't let them direct your development, but their insights should guide it. I've worked with a fantastic outsourced development firm for the past 20 months and can share more about the process I went through as a non-technical founder.
Some books I've found helpful are The Startup Owners Manual and Nail It, Then Scale It. Depending on where you live, I'd also suggest finding some fellow founders in your area just to start building that network too.
Good luck!