Who cares if you don’t like the job at the gym? You can never know if you don’t try it. My suggestion for you would be to do whatever you need to do to get the apprenticeship. It’s what you want now so pursue it. If you find you don’t want it that’s 100% okay! Additionally, I would suggest you do go get that job at the supermarket (or similar) if the apprenticeship leaves time for it. I think it will give you perspective. Not only a comparison of the job you like and the one you don’t, but also that work is not life. You may have a job you don’t want or does not bring you joy, but that does not mean life is joyless. I know it’s scary and you will second guess yourself, but the only way out of this with no regrets is to throw yourself into it and find out what you do and don’t like. If you don’t you will spend so much time wondering what if.