I need advise please as I am feeling really bad about an email that I sent?

to the owner and instructor of my jazzercise class. I have been going there for four months. In the beginning the owner was instructing all the morning classes. She was excellent and changed routines almost weekly which your body needs in order to keep working different areas of your body. I also have been an avid exerciser most of my life. Over the last two months there has been another instructor to teach class. I had no problem with her at all, however after two months and not changing the routine in any fashion, I became very uninterested in even going any more.Boredom and not challenging my body at all. I emailed the owner and told her that I was feeling very bored with the same routine and have had to make myself go for the last weeks. I asked her if she could possibly have the morning instructor add new routines. I did say that she had given me a all new meaning to bored to tears. Maybe I should not have said that.. I received no response however the next day the routine was new, workout was great. The owner was there and was very cool toward me. I then came home and sent a letter of apology asking her to please forgive me if I had offended anyone. No response. I am left feeling terrible. Did I do something terrible here?