Is it me?

My middle daughter has recently been bugging me a bit. We ask the kids to be polite to adults and that includes me and her father. We ask them to say "yes ma'am" "yes sir" etc., when we ask them to do things or when we talk to them about something they need to respond with "yes ma'am" or "no ma'am". We don't enforce it all the time and my son and my youngest daughter don't say it as often as we would like. My middle daughter though says it all the time.

Now, we shouldn't be upset about that, it is what we wanted, right? But when I ask her to do something, like take her plate to the sink, or help her sister with something, or pick up her coat, she says, "yes ma'am" like it is belaboring.

She has recently been watching the American Girl, Felicity and Samantha movies and is fascinated by the past, and I think that when she says "yes, ma'am" she is pretending to be like them. She says it in a polite, sweet voice, but it seems almost too sweet or too polite.

I should be happy she says it as often as we want her to say it and I sure hope that she is saying it to other adults too, but it is starting to grate on my nerves. It is that sugary sweet voice that she says it in, almost like as I said before she feels above what I am asking her to do.

Is it me or am I in for a heap of trouble when she gets to be 12?