I Can't Paint.

I am crippled by fear.
I got out all of my painting supplies and set them up on the table. I put the lamp nearby and turned it on, I pulled out all my paints and brushes and looked at pictures of landmarks for inspiration.
My brain says "No, you aren't an artist, don't try this, it will look like shit."
It's hard to ignore your own thoughts.
I hold this unrealistic expectation of myself, that everything I produce with my hands be high quality and beautiful. I allow myself no mistakes or exceptions.
I met an artist last week and her advice was to "let it flow."
HOW?