Can a positive self-image impede learning ?

Doing this months’s work I am wondering: If I build a wall of positive belief around myself, no critic will ever reach me. I’ll brush off anyone’s negative comments about my work for example as “whatever you think, I believe that I’m amazing at what I do”. That way, I will miss out on opportunities to question myself and grow. I might keep making stupid mistakes. Can your self-image be too positive?