Dear Evie & Felix,
This is one of those personal trivia questions that might come up in small talk or in a team-building exercise at work. Your answer says something about you, your childhood, and your family.
Mine was Guns N Roses at the Fargodome; I was 14.
Most adults can remember their first concert with no effort, but you're pretty young so I'll fill in some details for you: Rock the Garden 2015, featuring Belle and Sebastian, Conor Oberst, Courtney Barnett, Lucius, and thestand4rd.