I have said this before but
please consider the possible injury you can do to yourself where the instructor is not ensuring you are doing the exercise correctly.
I went to two classes Yoga and Pilates over two years ago and now have permanent nerve damage to my neck and face and back problems.
I was a person who had done gym work most of my adult life, windsurf and sail active not sedentary.
I only started classes because I had notice my balance wasn't good, had no problems doing any of the exercises so was not aware I was injuring myself.
Just something to consider.