Well, first impressions are often strongest and most lasting until something dramatic changes that. Pegs herself claimed to be useless. Since then she has proven herself and I think like any and everyone there would be a period of adjustment to these new circumstances (end of the world frikin zombie apocolypse!!) and finding yourself all over again. She has proven herself to some degree but due to her softness and first impressions will take some time for others to have full confidence in her.