You don't have to go to college to be a personal trainer. You can get certified through some accredited places like ACE, NSCA, NGA, NASM, NFPT, ISSA. Just look up those organizations and find the one that's right for you. I'm certified through NSCA and NASM, which are the two most highly recognized but also the hardest. I also have a CSCS from NSCA, but you have to have a bachelors degree in any field to take it. I've heard that ACE is pretty easy for newcomers getting used to the information and physiology. I'd start with them or NGA and then go into higher organizations after that.
I took 1 year of exercise physiology in college but ended up not going back for a 2nd year because I felt kind of like I was wasting my time. I make almost $35 an hour as an RN and my job will always be here and will always be stable vs if I wanted to be a full-time trainer it's a coin toss month to month and it's hard to work 12 hour shifts and go to college full-time. If you enjoy learning about the human body, I'd recommend you to go into the healthcare field if you think something like that would be for you.