She's just changing per developmental stages. AND your daughter is on the cusp, of an age change. This happens.
My kids did that too.
Bear in mind... a kid this age, CANNOT yet actually do, what they are thinking or wanting to do. But their cognition... is developing and they are getting more independent and yes, having "opinions" and expressing it.
You can at this age, start to teach her about emotions/feelings. I did when my kids were 2 years old.
You teach them the NAMES for feelings. ie: happy, sad, grumpy, frustrated, hungry, tired, etc. And teach them that they CAN tell you.... what they are feeling/thinking. Then, validate them... and help them cope or problem solve it. Even just repeating back to them, what they've said... can help. It teaches them... HOW to communicate. AND to 'know' their feelings.
Bear in mind, the "emotions" of a child, this age, is not even FULLY developed yet. Nor even in a 3 year old, They are just feeling it... but cannot yet be PRECISE about it... nor understand the abstractness of it.
Don't 'scold' for this... in your daughter. She is not fully even an 'expert' in knowing what she wants or exactly. It is confusing for them too. Just teach her... HOW to communicate, that you are there for her... and teach her the words for it.
A kid this age, is like a rock collecting moss... gradually they will become more 'aware' of themselves and what they want.
all the best,
Susan