beginning chain does not count as the first stitch, so, be sure to work your very first stitch in the same stitch as join.
round 12: ss into the next chain. chain 1. sc. chain 21. skip the next 7 chain 3 space. *sc in the next chain 3 space. chain 3.* repeat from * to * a total of 9 times. sc in the next chain 3 space. chain 21. skip the next 7 chain 3 spaces. *sc in the next chain 3 space. chain 3.* repeat from * to * around. join with a ss to the first sc made.
round 13: ss into the next chain. chain 1. *sc 