This is a nice sweater but picking the right size will depend on the look you are going for. I'm typically a small or medium (5'5", 125lbs, B34, rectangle shaped with a bit of a belly). I purchased a medium and it fit but it was cropped (barely reached the top of my high waisted jeans) and very fitted. If you are wanting a fitted, thicker sweater, purchase your regular size. If you are 5'5" or taller and need a bit more length, have larger than a B cup or were looking for a more relaxed fit so that you can wear this as a sweater/light jacket as pictured (the look I was going for), I highly suggest you size up. It's very cute though and I would recommend it.