Saleya was my first LV. I was looking at the size on internet, I thought I might wanted an MM, but when I went to store to actually see it, I felt MM was too big for me since I don't carry too much everyday. So I went for PM, and PM still fit a lot and will get very heavy. I think just your preference you like it on your shoulder or arm. I have no problem carry my PM on my shoulder. BTW, I'm 5'6