1950's vintage Ford 8N, when I was about 12.
But my 1973 Yamaha DT125, bought the same year, helped me master the clutch/throttle timing.
So, when I got to my first street car, a 1976 Peugeot 504 Diesel, the manual wasn't the challenge and I could focus on the rest of learning to drive on the road. Took my license test in that car in 1979. The examiner said something along the lines of, "diesel and a manual, too, eh, kid? You're brave..."