I've been singing my whole life. I'm a soprano. Also self taught in light classical / theatrical / opera music. I have sung for crowds and don't have a problem with it, but certainly do know the feeling of not being good enough. I recently sang at my grandmother's funeral. But not all alone, I sang along on a CD.

I have recently been given a sort of opportunity to join a choir. But I am so individual and so enjoy doing my own thing that I don't really want to. Also, am I really good enough?

So yes, I can understand.