Butterfly Curtain

Hi, this is my first curtain, and I’m already stuck right at the beginning. If I crochet a ladder stitch with the specified number of stitches, it’ll probably end up being a floor-length curtain. None of this matches the cm measurements 🙈—where am I going wrong?

Did you use thicker yarn than specified? Is there a gauge?
Otherwise, it’s best to contact the author directly. They’ll surely be able to help you best.;