You can't compare rates in California to rates in GA. Things cost more there and people get paid more. Things cost less here and people get paid less.
I know one coach who is $50 an hour but I would not use her for privates. I have 2 coaches I can use for privates who I think are great. One is $20/hour and the other is $25/hour. This is in the Atlanta metro area.
You can charge what the market will bear. If you have clients who will pay you $40+ an hour for privates and you are satisfied that your schedule is full enough, go for it. If you think you are not doing as many privates as you want to do maybe you are charging too much.