First off it is just NPTE, national physical therapy exam. Some states allow you to practice under a temporary license, which in those cases so long as you meet all the states requirements you could start working while studying for the NPTE, also some schools/states allow you to the the NPTE prior to graduation so that may be another option for you. As for taking the exam, you will register/submit an application for a state and then once they approve you, you will choose a Prometric testing center to take the test at, the testing center does not have to be in the state you wish to practice in.
You still have a while to worry about the NPTE process, just focus on passing classes at this point and worry about the test in a few years.