I need clarification for a part of the book Betrayed in the House of Night series.?

So I have been reading the House of Night Novels and I am on book 2: Betrayed. I am at the part where it is Zoey's first time leading the Dark Daughters ritual. Does she really have the affinity for all five elemets? I didn't quite understand because she also discovered that Stevie Rae has an affinity for earth, Shaunee has an affinity for fire, Erin has an affinity for water, and Damien has an affinity for air and it made me wonder if Zoey just thought that when she cast the circle she could summon all five elements or if it was because her friends were the ones who could gather the power of the elements.