It doesn't matter. It's easy to create ideas, but the hard part is actually building the game.
One of the best things a beginner can do is take inspiration from other games and essentially clone them. It helps them understand the amount of work that goes into making them, and provides a blueprint so you don't get lost with your "greatest ideas"..
You'll also have a higher chance of finishing the game.
Also, I wouldn't worry too much about being secretive about ideas- because why would you limit yourself to just a handful of ideas when you can literally make endless ideas. Chances are somebody has already thought of whatever it is you are thinking of anyways.
Also, you can't really afford to keep things secretive as an indie, especially if you don't have much experience, because you need to build an understanding of what will be successful if you have any serious goals. If you keep everything secretive, you might just find out later that your ideas weren't as great as you think they were, etc. So you might spend more time on something than was necessary.
Those are just some suggestions.