I'm not sure if it was my first print - but I still have a very old print, made by 1967/8 (I started printing after 20).
It was taken with my first 'decent' camera (not Brownie class), a Yashica rangefinder, 24x30cm enlargement.
It's a backlit warship, taken while I was in a ferry boat.

One of the reasons I started printing was that I've never liked small size pictures.

Jorge O