I've never seen "yatta" as an experession of anger, so I think she just says it because she dodged it. So it's "I've done it".

Caucasus said:

I've never seen "yatta" as an experession of anger, so I think she just says it because she dodged it. So it's "I've done it".

Yatta would be an expression of achievement only if it ends with that.
やったなあ would change the meaning to "Now you've pissed me off", where I agree with Nagumo's interpretation.
And she didn't really dodged it entirely.

Caucasus said:

I've never seen "yatta" as an experession of anger, so I think she just says it because she dodged it. So it's "I've done it".

There's still a "na". Can be either commentation or expression for anger toward the action from others.

It's tone and context would be something along the lines of "Now you've done it!" if that helps you grasp its meaning.