I agree with —, if you are enjoying it, keep developing it. If not, move on to your next idea.
One of the awesome things about this artform (computer games) is you can reuse code in other projects. So maybe this idea doesn't go anywhere (for you), but you may develop something you can use in another game.
Just keep going as long as you are interested in it. No use burning out on it either, so it's ok to drop it too. It's also ok to have MULTIPLE projects going at once. Most important thing is to just keep at it!