Well I was 21....but my 16 day (Yes 2 and a bit weeks!) old son has just been plonked in the seat of a C152 where I teach...now all I need to do is work out how to get the car seat strapped into the cockpit properly and safely so I can get him airborne so he can fly his first circuit with me!!!!
(give him a few more months & im sure itll be sorted!!)