About 20 years ago I started going to the gym to get ready for the next PB season; I never really stopped working out. Exercise can become its own reward. As much as todays workout might hurt it will be exponentially worse if u r trying to get in shape 10 - 20 years from now.
If u start early it becomes a routine
Consider what your trainer has to say but also listen to yourself. You may find a delight in certain exercises you wouldn't have expected. (there r lots of great marathons in Florida in the winter months