It's up to you whether to invite a personal trainer or not, but if you don't invite a personal trainer, their attitude will be different. As for why, you know.

Whether you hire a personal trainer or not, the trainer has the responsibility to tell you how to use the equipment.

Changsha is full of yoga people. Take up space early if you go. Whether it's good or not depends on your own taste. The key is whether you like the style of this tutor or not.