You can't bind off at the end of the row, so yes, you're binding off at the beginning of the rows 3 times each side.
The arm edge is the outer edge of your piece--where the sleeves are going to go. And yes, you're correct on the number of rows to knit.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry