Probably around 7 or 8. Started with box brownies, a kodak instamatic (126 or 127, can't remember off hand) and later allowed to use my dads Canon 8mm movie camera.
Got another camera around about 11 then really got interested when I was about 17 with a Zenith EM 35mm, then a year or so later got the then all new Canon AE1 35mm.
Think it was about £179 back in '77. (a lot of money back then).
Left it alone on & off pretty much since then, but got back into I suppose around '98 onwards.
Great hobby, if not expensive at times.