How could someone go about re-educating themselves to go back to college?

Im currently in a situation where I absolutely despise my life, I hate my job, I don't like where I work money is meh, Im at home with parents constantly saving, i personally love the gym, I love learning about it, I love learning about proper form and other things along side it, Ive thought about going back to college for maybe exercise science. But I failed the first time I was in college keep in mind this was years ago, and I told my parents I did not want to go and yet they forced me to go and I picked a major just to pick one. Im just curious because its been so long since Ive used my brain that Im not sure if I should even go back considering I feel like Im not at the level of college at the moment, How would I re-educate myself to get back to college learning level if I were to go back?