I think if your interest is strong, you should definitely take the leap and try to make it! I agree with some of the previous comments, it's impossible to judge whether or not the final game will be "good" just from reading the original concept, a lot can happen between the game's ideation and execution. But I think what you have so far has the potential to be a fun and fulfilling game and you should go for it. Even if it doesn't work out, you can learn from it and pick apart why, or get feedback as development goes on and make changes to improve your game. Your concept art is quite pretty and I'd love to see more if you decide to go through with it.
I agree wholeheartedly with Dune. If you love the concept, then run with it even if it doesn't work out in the end, experience is always something worth accumulating.
That said, greyboxing something is a great technique, if I'm remembering the right thing. It could speed up development and help you narrow down the core gameplay so you can get to the experience sooner and start cutting out needless parts.
One thing I'd ask is 'what is your core gameplay loop?' Like what would players be doing regularly and how can you make that core gameplay loop alone enjoyable, even before you add in more and more complex elements?