Tecnically not my very first experience, but in primary school I had to solve a math problem for my homework and an error in the book made it so that you couldn't solve it by hand (I think the solution was in the order of magnitude of 10^20). My calculator wasn't of much help either so I asked my dad to help me use basic to solve the problem. The next day I came in with a 2 page print out: 6 lines of code and the rest was the solution. The teacher didn't understand what it was.