How do I stop using 'neevu' with my elderly relatives?

I grew up hearing Kannada around the house, but I only spoke English back. Now that I’m trying to reconnect, I keep using formal 'neevu' out of habit, and my grandmother laughs at me because it sounds so stiff and distant. I want to sound natural and closer to family, but I’m terrified of accidentally using the wrong intimate verb endings. Is there a guide to navigating these honorifics for someone who can speak a bit but lacks the cultural nuance?