First pdp had how many bits?
If one looks up the history of DEC and even further looks at the pdp-1, they might find that it has 18 bits. Yes, there were DEC machines that were 12 bits (pdp-5, pdp-8, pdp-12), but the first one had 18 bits. Some of the DEC machines that had 18 bits were pdp-7, pdp-9, and pdp-15 (there may have been more).
Of course, one can also look to non-S/360 machines of IBM -- 36 bit 709/7094, and of course the IBM 1130 - 16 bits.
Real people used IBM's "personal computer" of the 60's: The IBM 1620. A marvelous computer to learn on.