I got Tofu when he was 1 year and 3 months. He is now 2 years and 8 months old. I changed his name right after we got him and it took him a few weeks to respond to that name. We never used his old name after we started calling him by his new one. As long as you keep on calling him that, I am sure he will respond to his name very soon. Good luck with the name change!