I think somebody has already asked this kind of question, but my situation is a little different.
My 2.5-year-old daughter has been in an increasingly-more-difficult period of "no" for 6 long months now.
She says no to everything, and however I ask her, gently, angrily, explaining the goals, etc. it does not work. I have to ask her almost 20 times to put on her shoes, to dress up, to brush her teeth, etc.
Sometimes she does things when asked, but a strategy that works the first time may cause a tantrum the next time, with cries and screams.
What is new now is that she agrees to do something at first, but then refuses, as a kind of test, I guess. For example, she asks to have a banana, and I ask her if she is sure. She says yes, I peel it, and then she doesn't even take a bite.
I (try to) keep calm and explain to her why I want her to put on her shoes, for example, but I always end up raising my voice at the end, and asking 1000 times a day is exhausting...
Aside from that, she can be very good. I think she is a little above average for her age: she speaks very well, is not overactive, goes to sleep well, and eats very well too.
My wife has been pregnant for 3 months, and our daughter has now been aware of the pregnancy for 1 month. She seems to act out more since this announcement, but she takes care of the future baby and plays mother a lot with her stuffed animals.
She has been potty trained for 1.5 months and sleeps in a bed without a barrier (which she asked to have removed), so she is making efforts to grow and learn.
I don't know what else to do. When she is being difficult, I tell she is "offside" (I got that from a Montessori book), and putt her in a room until she becomes calm again. She might cry for 5 minutes at most, but it still happens again and again.
Of course, I don't spank her.
Do you have an idea of what I can do? Can somebody please explain to me why she acts like this? Is it normal behavior?