Phat, not so silly, since even here in the US, only holdout for the old-fashioned measurement system, trekking poles are measured, or at least marked, in centimeters.
According to the cute little converter that comes with the "dashboard" on my iMac, 48 in. = 122 cm. Even for short folk like me, I wouldn't get them any shorter, just to be sure the poles will work with any shelter for which they might be needed in future.
EDIT, NEXT DAY: You'll also want 47-48" poles if you're interested in the ZPacks Twin Hexamid
under development. I suspect there may be others with similar height come along in the future.