You're afraid because you're thinking about the end, not about what you're doing.
See it in terms of paint. We don't learn subject matter, we learn paint. The musician can play any score that is set before him.
A painting is a collection of a series of corrections.
It's not what you paint. It's how you paint it. You don't have to paint elaborate things. Paint simple things as beautifully as you can.
If it's all wrong, it's all right.
You can't get it right, until you make it wrong.