Cute fabric! What does it look like when you turn the binding over to the other side? Does it still pucker? Where is join line for the two ends? I don't see it in the picture shown.
Do you starch and iron the binding before attaching to the quilt? I like to starch and press the binding. It is a personal preference to iron the binding in half though. I've done it both ways and generally don't iron it in Half.
After you join the binding seams, do a quick check on how it looks on the quilt. It should lay flat along the edge.
It might work to take out those stitches, starch and press, then re-attach to the quilt.
Good luck!