Impossible Goal

I am trying to evolve my Impossible Goal for 2021 as I can see my 2020 goal is achievable.
I think that being confident would be a good goal – It encompasses goals around being calmer, comfortable in my own skin and other metrics that I would like to achieve.
However, I am struggling to make ‘confidence’ a measurable goal. Any genius ideas??
How do I break down a nebulous feeling into structured goals?