Is it ironic that...

I responded to someones question that didnt end in a "?" using one of my own? The exchange: "Am I the only one who laughed really hard from 28:36 to 29:00." "Do you know what mark youre supposed to end a question with." Someone didnt realise I was joking, but I dont want to tell them it was irony in case it wasnt. (I had to remove all my apostrophes for the websites sake.)