First and foremost, I would challenge you to test the user experience and prove the concept of your product before building a mobile app. Mobile app development is not cheap and if you get the feature set wrong from a user standpoint, you will have spent money to develop blindly. Can you build a similar experience that provides value in a web application instead? You probably can. Even a few hundred users can get you the information you need to know almost exactly what the mobile app needs. There are mobile first websites that were around for years before they built the app just to make sure the experience was on par with what they expected. Test, test, test, and test again before jumping out there.