In the United States, all physical therapy programs are doctoral level, so you will need to get your undergraduate degree (4 years, typically) and then enroll in a Doctor of Physical Therapy (DPT) program that will last for 3 years. So, in total you will be in school for 7 years. A physical therapist assistant (PTA) program in an Associates degree, which is two years.
I recommend that no matter what your undergrad degree major is, that you make sure you meet the prerequisites of the PT schools you are intending to apply to. So, first, identify several PT schools that you want to apply to then go into the school's on-line catalog and see what each particular school requires for admission to PT school. For example, some schools may require a microbiology course or an advanced chemistry but others may not. Just be sure that you use your undergrad elective credits to take any courses outside of those required by your major that you may need to meet the PT prerequisites. And always apply to more than one PT school!
This sounds like a lot of time, and it is, but it is SO worth it! Donna