As a 1st year at Texas Tech, I will say the interview is pretty laid back. The professors are just looking to get to know you personally, not what is just on your application. Going in I would just look to know why you want to be a physical therapist and have basic background knowledge of the profession. APTA is an awesome source for information regarding the profession (Vision 2020, Evidence based practice, autonomy etc.). If you just be yourself you'll do fine, you've made it this far! If you have any other questions just let me know. Good Luck!