Are you in the U.S.? If so, I'm pretty sure you can't get a undergraduate degree in Physical Therapy. That is a graduate degree, not undergraduate.
You can get a degree in Kinesiology though, which is the degree I think you mean without realizing it.
It seems like a hard field to break into, and usually people who do it are former high-ish level athletes for a few reasons (i.e. connections, reputation, first hand experience, etc.). Getting a CSCS would likely be beneficial, and possibly a requirement though I'm not sure.