How to persuade my girlfriend to go to the gym together?

Well, it's really urgent. I think it may take several steps: 1. You can tell some things or jokes that you may be interested in during the exercise to attract her attention and say more. Then ask her to go with you when the time is almost the same. She can sit quietly and watch you practice. Find some projects that she can finish easily, ask her for help or invite her to participate. In the long run, she will be involved.

Wish you success!