Blame it on the moon

Yesterday I did some little writing on the wereanimal story, although I must admit the progress wasn't enough to further it toward the end. I expanded the first scene between Marcus and Zack. Just added details. Something I'm not good at when I'm first drafting a story. For a while I toyed with the idea of making this one the first chapter, but then I realized that it'd set the tone of a fast-paced action-packed plot for the story from the very beginning giving the readers the wrong impression so I discarded the idea. Frustrated, I went over the first 4 chapters, looking for grammatical errors, before sending it to Laura and Noelle for a brief critique in the hope that they might detect something I haven't. As I read it, I quickly noticed the time line was off. Because many of the characters are wereanimals and the club opens only during weekends, I forgot to take into consideration the full moon. I mean, I did take it into account when I wrote the scenes because some of the hero's reactions are affected by the moon, but I forgot how many weekends would be between one full moon and the next (the moon cycle). Now I have to sit down with my story and a calendar to figure this out. Have you ever had a problem missing a key element of story's timeline that makes it off?