Confidence, roughly speaking is a reflection of what you think of your own ability. Often times it is out of touch with reality.
Hence over-confident and under-confident.
Many people recommend humility which would suggest leaning toward under confident. Which means erroring on the side of believing you’re not as good as you actually are.
But that’s no way to grow. That will hold you back.
You should error on the side of overconfident.
Imagine measuring skill and confidence separately. I’m suggesting that if skill is at 50% that confidence should be at 55% not 45%.
Because then you’ll take healthy risks to take your skill to the next level. If you’re under confident you won’t push yourself to try new things because you’ll doubt your ability to do what you already can do.
In other words you’ll stay in your comfort zone and stagnate.
Always make sure your confidence leads your skill, it’ll then pull your skill up instead of down. Unless of course you don’t want to grow.