Here is what I’ve discovered about people. Some have an extremely high measurement of what is called ‘Responsibility’ by The Gallup Organization.
Responsibility
Your Responsibility theme forces you to take psychological ownership for anything you commit to, and whether large or small, you feel emotionally bound to follow it through to completion. Your good name depends on it. If for some reason you cannot deliver, you automatically start to look for ways to make it up to the other person. Apologies are not enough. Excuses and rationalizations are totally unacceptable. You will not quite be able to live with yourself until you have made restitution. This conscientiousness, this near obsession for doing things right, and your impeccable ethics, combine to create your reputation: utterly dependable. When assigning new responsibilities, people will look to you first because they know it will get done. When people come to you for help—and they soon will—you must be selective. Your willingness to volunteer may sometimes lead you to take on more than you should. Source
So, let’s say that some of these family members who are passing judgement have a high level of this characteristic. It’s one thing if they live by this Strength, but it becomes a Weakness when they expect others to act the same way in all circumstances. There are just some times where the rules should be bent, as long as it isn’t impacting others. From what you have described so far, it doesn’t sound like it.
If I were in your shoes, I would ask these tut-tutters a couple of questions, just like you have allowed us to do. “I respect your opinion, so help me to understand what the objections are.” Once they give one, ask “What else should I take into consideration?” Keep asking this until they cannot come up with a new one. Then answer each one, like you are doing here.
My guess is that these are people who don’t know the full story. They may also have been subjected to attending some sort of lesson no matter how they felt about it as a child, and figure, if they had to do it and survived, so can your children. Then again, they might come up with a valid reason that you haven’t thought of yet.
My three remaining questions for you are: 1.) Is the instructor being notified in advance that the daughter(s) won’t be attending? 2.) How will this impact the instructor’s schedule and demeanor towards you and your daughters? 3.) How might this impact your daughters’ view on not following up with a commitment if they are allowed to skip an occasional class?