Letter Carrier Hung

My mailman wrote back. His name is Hung. He is Vietnamese. He said in eighteen years of being a letter carrier, no one on his route has ever written to him before so he was especially touched by my note introducing myself. My only question is why it took him so long to respond. Maybe I’ll write him back. Would that be ironic if I started a written correspondence with my letter carrier or am I misusing the word “ironic”?