S, Don't be scared of doing something new and meeting new people. You will soon know that people are people just like you and me...we ingest, digest and egest. About the part where you are not good enough...remember they offered you a place and registered you as a PhD student, so that means that if you are not good enough then that uni is not good enough. You will be surprised that some supervisors have a Mphil/MRes or Msc, so you are good enough.