I just tried out a group fitness class for the 1st time after working out at home with exercise videos for more than 4 years. Now, the trainer/instructor did not correct form of the class, but kept pushing us to do the exercises faster. He has been known to get results in the members who attend (weight loss, tone, strength, etc). I don't want to suffer from exercise-related injury which I think the members will suffer if they keep this up with him. At the same time, I tend to not push myself hard enough when I am working out solo at home. I can't seem to make up my mind to join this class for a month as I need to lose 2-4 lbs within a month for my cousin's wedding. What do I do? Should I join or not?