Yes, get a longer one. A 16" is okay for a cowl, maybe that's what she was thinking. But for a longer one, the sts won't be so crowded if you get one about 30" or so. You don't need one as long a 40 or 47", the extra length of the cord tends to get in the way, and one that's around 29 or 32" is a lot more versatile for other projects, like sweaters or smaller blankets.
sue- knitting heretic