I've been 12 years old for awhile.
I started a little earlier than that with a electronic kit that allowed you to connect components with springs and wires. It had 2 transistors and a number of other components such capacitors, resistors and a diode to make a simple AM radio.
I stole that line from a friend. He is into FPV and RC airplanes. He said his career goal is to be 12 years old forever.