She's an Easter Egger. Ameracuanas are a pure breed of chicken that only come in a few color varieties: Black, Blue, Blue Wheaten, Brown Red, Buff, Silver, Wheaten, and White. Ameraucanas also have blue legs; if a bird doesn't have blue legs, even if it has a similar color pattern, it is not an Ameraucana.
Easter Eggers are crosses of Ameraucanas, Araucanas, and higher-production, brown-egg laying birds. They lay greenish or pinkish eggs, and exhibit some of the same characteristics as a pure breed, but differ in color pattern, leg color, and egg color (pure Ameraucanas or Araucanas lay blue eggs, not green). Unless you plan to show, Easter Eggers are just as good as their pure bred relatives.
Hope this helps! You have a very pretty Easter Egger!