Didn’t really want to go down this route but since you guys wanted to I would also point out the OP likely hasn’t been making $500/mo for a full year yet so to make that kind of projection is premature. I think at best he will make that for a few months then it will taper off within the year as the app gets less popular.
You can’t just say your app makes $500/mo without giving the time period for how long it has been making that. Generally if it’s not revealed it’s because it hasn’t been very long.