"On the other hand, I have to agree with Helena 6 that Anne herself seems extremely reserved, perhaps for reasons that are not her fault, but still, she is. In fact, the whole novel seems to be blanketed in excessive reserve, IMO!"

Anne's unreserved moments have been more and more frequent:

In her meetings with Mr. Elliot in chapter 15-16, she becomes increasingly unreserved and comfortable, going so far as to extend her opinion of the Dalrymples to him.

In chapter 17 she withstands the severe criticism of her father to keep her appointment with Mrs. Smith. I only wish she had not so much a sense of personal respect for her father that she was unwilling to draw the comparison aloud between Mrs. Clay and Mrs. Smith.

Later in that chapter, despite Lady R's emotional blackmail, Anne sticks to her guns and maintains the she and Mr. Elliot would not suit.

In Chapter 18, she is certainly unreserved with the Admiral, though she is not quick enough in her pronouncements with him to make herself understood. Still she tries to be frank and she does contradict him to defend Benwick.

Chapter 19 marks a turning point, despite her having to rationalize a reason to leave her party, she does seek out FW, instead of hiding from him. A first.

She continues this seeking out hoping to make ammends for snubs from Elizabeth and Lady Russell, she literally steps out of line at the concert (chapter 20) to greet him. This is one small step for woman, one giant leap forward for Anne Elliott. She is rewarded by a conversation, an actual, honest conversation with Captain Wentworth, where they almost discuss things frankly. She is in such high spirits from this encounter that she is almost flirtatcious with Mr. Elliot. This chapter ends with Anne attempting to lure the Captain into sitting next to her, another bold step forward. (Not quite P2's running after him, but in a certain sense it is as just as a dramatic a change).