For me it was in late 60’s when my brother was given the Hornby Albert Hall set and Pullman coaches that we set up on kitchen table. He lost interest but wouldn’t let me have it so I was given a circle of track and I think a dock tank with a wagon by my grandfather. This was then added to over next few years with a rural rambler set which fuelled the imagination for years and finally a class 47 loco. I think I was about 14 when I managed to get a sheet of 8x4 chipboard and tried to make a layout as dad wasn’t at all handymanish it was a failure and never finished, so no change there then!. Still remember it like it was yesterday..
P.S I was fired up by a present of a years Railway Modeller subscription which I then went on to save my pocket money until stopped buying in the 2000’s kept them till last move the slashed and scanned and I. Now still enjoying them rather than them gathering dust and slung out.