Personal training is not a road to riches. Yes, there are the PTs to the movie stars and athletes who are able to command retainers and $200 an hour plus fees, but the vast majority struggle to make a decent living, especially at the beginning.
Do the math. If you want to make say $50,000 a year pre tax, figure out how many sessions you would have to do a week at $35, $50, whatever the going rate is in your area for a new PT. It would be 20-30 sessions a week, EVERY week, 52 weeks a year ( and starting out, it is going to take awhile to get enough clients to even come close to that). Then subtract taxes, liability insurance, health insurance, the take the health club gets, licensing fees ( if any) and there is not much left. That kind of schedule also does not leave much time for your own training if you want to be a serious trainer. You are also going to have to spend alot of hours (unpaid) in your early months marketing yourself to build up a client base and I know of at least one major health club chain that has monthly quotas of PT sessions a trainer must meet, with the penalty of losing your job if you do not meet those minimums.
It would be a much better idea to get a degree in something else that will allow you to earn much more money, then study for a PT certification and maybe work as a part time PT until you have sufficient financial security, assets built up, a client base and a reputation in the field where you can afford to take the risk of going into full time personal training.
As someone else said, spending the money for college tuition to earn a degree that will take you into personal training is financially foolish.