I was struck too by Anne actually persuading others: she persuades Capt. Benwick to read more prose, for example. And she is thought by the Musgroves to have some persuading power over Mary (and by Mary to have some power over Charles and the children).

She knows when to yield and when to persuade. She has a perfectly balanced character.

I would say the "turning point" in the novel is when Anne openly aknowledges to herself that Capt. Wentworth was wrong in his unreserved praise of a firm character as opposed to a yielding one. It feels like this is the point when she really makes peace with herself.

"Anne wondered whether it ever occurred to him now, to question the justness of his own previous opinion as to the universal felicity and advantage of firmness of character; and whether it might not strike him that, like all other qualities of the mind, it should have its proportions and limits. She thought it could scarcely escape him to feel that a persuadable temper might sometimes be as much in favour of happiness as a very resolute character".