depends on the pattern. if you are knitting a scarf flat, for example, it doesn't matter.
if, however, you are knitting a hat in the round and the pattern calls for 16 inch and all you have is 24 inch you would have to consider whether your head is 24 inches around!
the smalles Denise is 17 inches but it should probably work for you. just depends on how small of a head you are needing to fit.