What prevents me from starting something.

Usually what prevents me from starting a project or an assignment is the feeling of not doing it right. I have a lingering fear of rejection that only becomes present before I start an assignment. I get myself all ready to do a project and then the feeling strikes and I go into panic mode and brush it off until I have some sort of either inspiration or motive for starting. I was having doubts on starting this assignment but then I remembered if I brush it off I would get a zero so that pushed me to at least write something down. To get myself to start I have to isolate myself from everything. People, technology, my instruments or even a broom because when I want to avoid stuff I would go as far as to start cleaning my whole house.